{"id":1173,"date":"2010-10-21T21:20:37","date_gmt":"2010-10-21T13:20:37","guid":{"rendered":"http:\/\/www.zhangxinxu.com\/wordpress\/?p=1173"},"modified":"2018-01-01T19:49:54","modified_gmt":"2018-01-01T11:49:54","slug":"%e7%bf%bb%e8%af%91-%e9%ab%98%e8%b4%a8%e9%87%8fjavascript%e4%bb%a3%e7%a0%81%e4%b9%a6%e5%86%99%e5%9f%ba%e6%9c%ac%e8%a6%81%e7%82%b9","status":"publish","type":"post","link":"https:\/\/www.zhangxinxu.com\/wordpress\/2010\/10\/%e7%bf%bb%e8%af%91-%e9%ab%98%e8%b4%a8%e9%87%8fjavascript%e4%bb%a3%e7%a0%81%e4%b9%a6%e5%86%99%e5%9f%ba%e6%9c%ac%e8%a6%81%e7%82%b9\/","title":{"rendered":"\u7ffb\u8bd1-\u9ad8\u8d28\u91cfJavaScript\u4ee3\u7801\u4e66\u5199\u57fa\u672c\u8981\u70b9"},"content":{"rendered":"<p>by <a href=\"http:\/\/www.zhangxinxu.com\/\">zhangxinxu<\/a> from <a href=\"http:\/\/www.zhangxinxu.com\/\">http:\/\/www.zhangxinxu.com<\/a><br \/>\n\u672c\u6587\u5730\u5740\uff1a<a href=\"http:\/\/www.zhangxinxu.com\/wordpress\/?p=1173\">http:\/\/www.zhangxinxu.com\/wordpress\/?p=1173<\/a><\/p>\n<style>.cg{color:green;}.cdg{color:#069; font-weight:bold;}.g9{color:#999; }<\/style>\n<div id=\"link\">\n\t\u539f\u6587\u4f5c\u8005\uff1a<a href=\"www.phpied.com\" target=\"_blank\">Stoyan Stefanov<\/a><br \/>\n    \u539f\u6587\u94fe\u63a5\uff1a<a href=\"http:\/\/net.tutsplus.com\/tutorials\/javascript-ajax\/the-essentials-of-writing-high-quality-javascript\/\" target=\"_blank\">The Essentials of Writing High Quality JavaScript <\/a><br \/>\n    \u7ffb\u8bd1\u7f16\u8f91\uff1a<a href=\"http:\/\/www.zhangxinxu.com\/\">\u5f20\u946b\u65ed<\/a>\n<\/div>\n<p><span class=\"s\">\/\/zxx: \u4fd7\u4e0d\u53ef\u8010\u7684\u5f00\u573a\u767d\u5c31\u514d\u4e86\uff0c\u76f4\u63a5\u8fdb\u5165\u7ffb\u8bd1\u5185\u5bb9\uff08\u5176\u5b9e\u662f\u56e0\u4e3a\u672c\u6587\u662f\u5728\u592a..\u592a..\u957f\u4e86\uff0c<img decoding=\"async\" src=\"http:\/\/a.xnimg.cn\/imgpro\/emotions\/tie\/21.gif?ver=1\" title=\"\u6655\" alt=\"\u6655\" emotion=\"(\u6655)\">\uff09\u3002<\/span><\/p>\n<p style=\"line-height:20px; padding:15px; background:#fcfcfc; border:1px solid #e0e0e0; font-size:12px;\">\n\t<strong style=\"color:#066;\">\u6559\u7a0b\u76f8\u5173\u7ec6\u8282<\/strong><br \/>\n    <strong>\u4e3b\u9898\uff1a<\/strong>JavaScript\u6700\u4f73\u5b9e\u8df5<br \/>\n    <strong>\u96be\u5ea6\u4f30\u8ba1\uff1a<\/strong>\u4e2d\u7b49\n<\/p>\n<p>\u624d\u534e\u6a2a\u6ea2\u7684<a href=\"http:\/\/www.phpied.com\">Stoyan Stefanov<\/a>\uff0c\u5728\u4ed6\u5199\u7684\u7531<a href=\"http:\/\/oreilly.com\/\">O\u2019Reilly<\/a>\u521d\u7248\u7684\u65b0\u4e66<a href=\"http:\/\/amzn.to\/93szK7\">\u300aJavaScript Patterns\u300b<\/a>(JavaScript\u6a21\u5f0f)\u4e2d\uff0c\u6211\u60f3\u8981\u662f\u4e3a\u6211\u4eec\u7684\u8bfb\u8005\u8d21\u732e\u5176\u6458\u8981\uff0c\u90a3\u4f1a\u662f\u4ef6\u5f88\u7f8e\u5999\u7684\u4e8b\u60c5\u3002\u5177\u4f53\u4e00\u70b9\u5c31\u662f\u7f16\u5199\u9ad8\u8d28\u91cfJavaScript\u7684\u4e00\u4e9b\u8981\u7d20\uff0c\u4f8b\u5982\u907f\u514d\u5168\u5c40\u53d8\u91cf\uff0c\u4f7f\u7528\u5355\u53d8\u91cf\u58f0\u660e\uff0c\u5728\u5faa\u73af\u4e2d\u9884\u7f13\u5b58length(\u957f\u5ea6)\uff0c\u9075\u5faa\u4ee3\u7801\u9605\u8bfb\uff0c\u4ee5\u53ca\u66f4\u591a\u3002<\/p>\n<p>\u6b64\u6458\u8981\u4e5f\u5305\u62ec\u4e00\u4e9b\u4e0e\u4ee3\u7801\u4e0d\u592a\u76f8\u5173\u7684\u4e60\u60ef\uff0c\u4f46\u5bf9\u6574\u4f53\u4ee3\u7801\u7684\u521b\u5efa\u606f\u606f\u76f8\u5173\uff0c\u5305\u62ec\u64b0\u5199API\u6587\u6863\u3001\u6267\u884c\u540c\u884c\u8bc4\u5ba1\u4ee5\u53ca\u8fd0\u884cJSLint\u3002\u8fd9\u4e9b\u4e60\u60ef\u548c\u6700\u4f73\u505a\u6cd5\u53ef\u4ee5\u5e2e\u52a9\u4f60\u5199\u51fa\u66f4\u597d\u7684\uff0c\u66f4\u6613\u4e8e\u7406\u89e3\u548c\u7ef4\u62a4\u7684\u4ee3\u7801\uff0c\u8fd9\u4e9b\u4ee3\u7801\u5728\u51e0\u4e2a\u6708\u6216\u662f\u51e0\u5e74\u4e4b\u540e\u518d\u56de\u8fc7\u5934\u770b\u770b\u4e5f\u662f\u4f1a\u89c9\u5f97\u5f88\u81ea\u8c6a\u7684\u3002<\/p>\n<h3>\u4e66\u5199\u53ef\u7ef4\u62a4\u7684\u4ee3\u7801(Writing Maintainable Code )<\/h3>\n<p>\u8f6f\u4ef6bug\u7684\u4fee\u590d\u662f\u6602\u8d35\u7684\uff0c\u5e76\u4e14\u968f\u7740\u65f6\u95f4\u7684\u63a8\u79fb\uff0c\u8fd9\u4e9bbug\u7684\u6210\u672c\u4e5f\u4f1a\u589e\u52a0\uff0c\u5c24\u5176\u5f53\u8fd9\u4e9bbug\u6f5c\u4f0f\u5e76\u6162\u6162\u51fa\u73b0\u5728\u5df2\u7ecf\u53d1\u5e03\u7684\u8f6f\u4ef6\u4e2d\u65f6\u3002\u5f53\u4f60\u53d1\u73b0bug\u7684\u65f6\u5019\u5c31\u7acb\u5373\u4fee\u590d\u5b83\u662f\u6700\u597d\u7684\uff0c\u6b64\u65f6\u4f60\u4ee3\u7801\u8981\u89e3\u51b3\u7684\u95ee\u9898\u5728\u4f60\u8111\u4e2d\u8fd8\u662f\u5f88\u6e05\u6670\u7684\u3002\u5426\u5219\uff0c\u4f60\u8f6c\u79fb\u5230\u5176\u4ed6\u4efb\u52a1\uff0c\u5fd8\u4e86\u90a3\u4e2a\u7279\u5b9a\u7684\u4ee3\u7801\uff0c\u4e00\u6bb5\u65f6\u95f4\u540e\u518d\u53bb\u67e5\u770b\u8fd9\u4e9b\u4ee3\u7801\u5c31\u9700\u8981\uff1a<\/p>\n<ul id=\"ul\">\n<li>\u82b1\u65f6\u95f4\u5b66\u4e60\u548c\u7406\u89e3\u8fd9\u4e2a\u95ee\u9898<\/li>\n<li>\u5316\u65f6\u95f4\u662f\u4e86\u89e3\u5e94\u8be5\u89e3\u51b3\u7684\u95ee\u9898\u4ee3\u7801<\/li>\n<\/ul>\n<p>\u8fd8\u6709\u95ee\u9898\uff0c\u7279\u522b\u5bf9\u4e8e\u5927\u7684\u9879\u76ee\u6216\u662f\u516c\u53f8\uff0c\u4fee\u590dbug\u7684\u8fd9\u4f4d\u4f19\u8ba1\u4e0d\u662f\u5199\u4ee3\u7801\u7684\u90a3\u4e2a\u4eba\uff08\u4e14\u53d1\u73b0bug\u548c\u4fee\u590dbug\u7684\u4e0d\u662f\u540c\u4e00\u4e2a\u4eba\uff09\u3002\u56e0\u6b64\uff0c\u5fc5\u987b\u964d\u4f4e\u7406\u89e3\u4ee3\u7801\u82b1\u8d39\u7684\u65f6\u95f4\uff0c\u65e0\u8bba\u662f\u4e00\u6bb5\u65f6\u95f4\u524d\u4f60\u81ea\u5df1\u5199\u7684\u4ee3\u7801\u8fd8\u662f\u56e2\u961f\u4e2d\u7684\u5176\u4ed6\u6210\u5458\u5199\u7684\u4ee3\u7801\u3002\u8fd9\u5173\u7cfb\u5230\u5e95\u7ebf\uff08\u8425\u4e1a\u6536\u5165\uff09\u548c\u5f00\u53d1\u4eba\u5458\u7684\u5e78\u798f\uff0c\u56e0\u4e3a\u6211\u4eec\u66f4\u5e94\u8be5\u53bb\u5f00\u53d1\u65b0\u7684\u6fc0\u52a8\u4eba\u5fc3\u7684\u4e8b\u7269\u800c\u4e0d\u662f\u82b1\u51e0\u5c0f\u65f6\u51e0\u5929\u7684\u65f6\u95f4\u53bb\u7ef4\u62a4\u9057\u7559\u4ee3\u7801\u3002<\/p>\n<p>\u53e6\u4e00\u4e2a\u76f8\u5173\u8f6f\u4ef6\u5f00\u53d1\u751f\u547d\u7684\u4e8b\u5b9e\u662f\uff0c\u8bfb\u4ee3\u7801\u82b1\u8d39\u7684\u65f6\u95f4\u8981\u6bd4\u5199\u6765\u5f97\u591a\u3002\u6709\u65f6\u5019\uff0c\u5f53\u4f60\u4e13\u6ce8\u5e76\u6df1\u5165\u601d\u8003\u67d0\u4e2a\u95ee\u9898\u7684\u65f6\u5019\uff0c\u4f60\u53ef\u4ee5\u5750\u4e0b\u6765\uff0c\u4e00\u4e2a\u4e0b\u5348\u5199\u5927\u91cf\u7684\u4ee3\u7801\u3002<\/p>\n<p>\u4f60\u7684\u4ee3\u7801\u5f88\u80fd\u5f88\u5feb\u5c31\u5de5\u4f5c\u4e86\uff0c\u4f46\u662f\uff0c\u968f\u7740\u5e94\u7528\u7684\u6210\u719f\uff0c\u8fd8\u4f1a\u6709\u5f88\u591a\u5176\u4ed6\u7684\u4e8b\u60c5\u53d1\u751f\uff0c\u8fd9\u5c31\u8981\u6c42\u4f60\u7684\u8fdb\u884c\u8fdb\u884c\u5ba1\u67e5\uff0c\u4fee\u6539\uff0c\u548c\u8c03\u6574\u3002\u4f8b\u5982\uff1a<\/p>\n<ul id=\"ul\">\n<li>bug\u662f\u66b4\u9732\u7684<\/li>\n<li>\u65b0\u529f\u80fd\u88ab\u6dfb\u52a0\u5230\u5e94\u7528\u7a0b\u5e8f<\/li>\n<li>\u7a0b\u5e8f\u5728\u65b0\u7684\u73af\u5883\u4e0b\u5de5\u4f5c\uff08\u4f8b\u5982\uff0c\u5e02\u573a\u4e0a\u51fa\u73b0\u65b0\u60f3\u6d4f\u89c8\u5668\uff09<\/li>\n<li>\u4ee3\u7801\u6539\u53d8\u7528\u9014<\/li>\n<li>\u4ee3\u7801\u5f97\u5b8c\u5168\u4ece\u5934\u91cd\u65b0\uff0c\u6216\u79fb\u690d\u5230\u53e6\u4e00\u4e2a\u67b6\u6784\u4e0a\u6216\u8005\u751a\u81f3\u4f7f\u7528\u53e6\u4e00\u79cd\u8bed\u8a00<\/li>\n<\/ul>\n<p>\u7531\u4e8e\u8fd9\u4e9b\u53d8\u5316\uff0c\u5f88\u5c11\u4eba\u529b\u6570\u5c0f\u65f6\u5199\u7684\u4ee3\u7801\u6700\u7ec8\u6f14\u53d8\u6210\u82b1\u6570\u5468\u6765\u9605\u8bfb\u8fd9\u4e9b\u4ee3\u7801\u3002\u8fd9\u5c31\u662f\u4e3a\u4ec0\u4e48\u521b\u5efa\u53ef\u7ef4\u62a4\u7684\u4ee3\u7801\u5bf9\u5e94\u7528\u7a0b\u5e8f\u7684\u6210\u529f\u81f3\u5173\u91cd\u8981\u3002<\/p>\n<p>\u53ef\u7ef4\u62a4\u7684\u4ee3\u7801\u610f\u5473\u7740\uff1a<\/p>\n<ul id=\"ul\">\n<li>\u53ef\u8bfb\u7684<\/li>\n<li>\u4e00\u81f4\u7684<\/li>\n<li>\u53ef\u9884\u6d4b\u7684<\/li>\n<li>\u770b\u4e0a\u53bb\u5c31\u50cf\u662f\u540c\u4e00\u4e2a\u4eba\u5199\u7684<\/li>\n<li>\u5df2\u8bb0\u5f55<\/li>\n<\/ul>\n<h3>\u6700\u5c0f\u5168\u5c40\u53d8\u91cf(Minimizing Globals)<\/h3>\n<p>JavaScript\u901a\u8fc7\u51fd\u6570\u7ba1\u7406\u4f5c\u7528\u57df\u3002\u5728\u51fd\u6570\u5185\u90e8\u58f0\u660e\u7684\u53d8\u91cf\u53ea\u5728\u8fd9\u4e2a\u51fd\u6570\u5185\u90e8\uff0c\u51fd\u6570\u5916\u9762\u4e0d\u53ef\u7528\u3002\u53e6\u4e00\u65b9\u9762\uff0c\u5168\u5c40\u53d8\u91cf\u5c31\u662f\u5728\u4efb\u4f55\u51fd\u6570\u5916\u9762\u58f0\u660e\u7684\u6216\u662f\u672a\u58f0\u660e\u76f4\u63a5\u7b80\u5355\u4f7f\u7528\u7684\u3002<\/p>\n<p>\u6bcf\u4e2aJavaScript\u73af\u5883\u6709\u4e00\u4e2a\u5168\u5c40\u5bf9\u8c61\uff0c\u5f53\u4f60\u5728\u4efb\u610f\u7684\u51fd\u6570\u5916\u9762\u4f7f\u7528this\u7684\u65f6\u5019\u53ef\u4ee5\u8bbf\u95ee\u5230\u3002\u4f60\u521b\u5efa\u7684\u6bcf\u4e00\u4e2a\u5168\u90e8\u53d8\u91cf\u90fd\u6210\u4e86\u8fd9\u4e2a\u5168\u5c40\u5bf9\u8c61\u7684\u5c5e\u6027\u3002\u5728\u6d4f\u89c8\u5668\u4e2d\uff0c\u65b9\u4fbf\u8d77\u89c1\uff0c\u8be5\u5168\u5c40\u5bf9\u8c61\u6709\u4e2a\u9644\u52a0\u5c5e\u6027\u53eb\u505awindow\uff0c\u6b64window(\u901a\u5e38)\u6307\u5411\u8be5\u5168\u5c40\u5bf9\u8c61\u672c\u8eab\u3002\u4e0b\u9762\u7684\u4ee3\u7801\u7247\u6bb5\u663e\u793a\u4e86\u5982\u4f55\u5728\u6d4f\u89c8\u5668\u73af\u5883\u4e2d\u521b\u5efa\u548c\u8bbf\u95ee\u7684\u5168\u5c40\u53d8\u91cf\uff1a<\/p>\n<div class=\"zxx_code\">\n<pre>\nmyglobal = \"hello\"; <span class=\"cg\">\/\/ \u4e0d\u63a8\u8350\u5199\u6cd5<\/span>\nconsole.log(myglobal); <span class=\"cg\">\/\/ \"hello\"<\/span>\nconsole.log(window.myglobal); <span class=\"cg\">\/\/ \"hello\"<\/span>\nconsole.log(window[\"myglobal\"]); <span class=\"cg\">\/\/ \"hello\"<\/span>\nconsole.log(this.myglobal); <span class=\"cg\">\/\/ \"hello\"<\/span>\n<\/pre>\n<\/div>\n<h3>\u5168\u5c40\u53d8\u91cf\u7684\u95ee\u9898<\/h3>\n<p>\u5168\u5c40\u53d8\u91cf\u7684\u95ee\u9898\u5728\u4e8e\uff0c\u4f60\u7684JavaScript\u5e94\u7528\u7a0b\u5e8f\u548cweb\u9875\u9762\u4e0a\u7684\u6240\u6709\u4ee3\u7801\u90fd\u5171\u4eab\u4e86\u8fd9\u4e9b\u5168\u5c40\u53d8\u91cf\uff0c\u4ed6\u4eec\u4f4f\u5728\u540c\u4e00\u4e2a\u5168\u5c40\u547d\u540d\u7a7a\u95f4\uff0c\u6240\u4ee5\u5f53\u7a0b\u5e8f\u7684\u4e24\u4e2a\u4e0d\u540c\u90e8\u5206\u5b9a\u4e49\u540c\u540d\u4f46\u4e0d\u540c\u4f5c\u7528\u7684\u5168\u5c40\u53d8\u91cf\u7684\u65f6\u5019\uff0c\u547d\u540d\u51b2\u7a81\u5728\u6240\u96be\u514d\u3002<\/p>\n<p>web\u9875\u9762\u5305\u542b\u4e0d\u662f\u8be5\u9875\u9762\u5f00\u53d1\u8005\u6240\u5199\u7684\u4ee3\u7801\u4e5f\u662f\u6bd4\u8f83\u5e38\u89c1\u7684\uff0c\u4f8b\u5982\uff1a<\/p>\n<ul id=\"ul\">\n<li>\u7b2c\u4e09\u65b9\u7684JavaScript\u5e93<\/li>\n<li>\u5e7f\u544a\u65b9\u7684\u811a\u672c\u4ee3\u7801<\/li>\n<li>\u7b2c\u4e09\u65b9\u7528\u6237\u8ddf\u8e2a\u548c\u5206\u6790\u811a\u672c\u4ee3\u7801<\/li>\n<li>\u4e0d\u540c\u7c7b\u578b\u7684\u5c0f\u7ec4\u4ef6\uff0c\u6807\u5fd7\u548c\u6309\u94ae<\/li>\n<\/ul>\n<p>\u6bd4\u65b9\u8bf4\uff0c\u8be5\u7b2c\u4e09\u65b9\u811a\u672c\u5b9a\u4e49\u4e86\u4e00\u4e2a\u5168\u5c40\u53d8\u91cf\uff0c\u53eb\u505aresult\uff1b\u63a5\u7740\uff0c\u5728\u4f60\u7684\u51fd\u6570\u4e2d\u4e5f\u5b9a\u4e49\u4e00\u4e2a\u540d\u4e3aresult\u7684\u5168\u5c40\u53d8\u91cf\u3002\u5176\u7ed3\u679c\u5c31\u662f\u540e\u9762\u7684\u53d8\u91cf\u8986\u76d6\u524d\u9762\u7684\uff0c\u7b2c\u4e09\u65b9\u811a\u672c\u5c31\u4e00\u4e0b\u5b50\u55dd\u5c41\u5566\uff01<\/p>\n<p>\u56e0\u6b64\uff0c\u8981\u60f3\u548c\u5176\u4ed6\u811a\u672c\u6210\u4e3a\u597d\u90bb\u5c45\u7684\u8bdd\uff0c\u5c3d\u53ef\u80fd\u5c11\u7684\u4f7f\u7528\u5168\u5c40\u53d8\u91cf\u662f\u5f88\u91cd\u8981\u7684\u3002\u5728\u4e66\u4e2d\u540e\u9762\u63d0\u5230\u7684\u4e00\u4e9b\u51cf\u5c11\u5168\u5c40\u53d8\u91cf\u7684\u7b56\u7565\uff0c\u4f8b\u5982\u547d\u540d\u7a7a\u95f4\u6a21\u5f0f\u6216\u662f\u51fd\u6570\u7acb\u5373\u81ea\u52a8\u6267\u884c\uff0c\u4f46\u662f\u8981\u60f3\u8ba9\u5168\u5c40\u53d8\u91cf\u5c11\u6700\u91cd\u8981\u7684\u8fd8\u662f\u59cb\u7ec8\u4f7f\u7528var\u6765\u58f0\u660e\u53d8\u91cf\u3002<\/p>\n<p>\u7531\u4e8eJavaScript\u7684\u4e24\u4e2a\u7279\u5f81\uff0c\u4e0d\u81ea\u89c9\u5730\u521b\u5efa\u51fa\u5168\u5c40\u53d8\u91cf\u662f\u51fa\u4e4e\u610f\u6599\u7684\u5bb9\u6613\u3002\u9996\u5148\uff0c\u4f60\u53ef\u4ee5\u751a\u81f3\u4e0d\u9700\u8981\u58f0\u660e\u5c31\u53ef\u4ee5\u4f7f\u7528\u53d8\u91cf\uff1b\u7b2c\u4e8c\uff0cJavaScript\u6709\u9690\u542b\u7684\u5168\u5c40\u6982\u5ff5\uff0c\u610f\u5473\u7740\u4f60\u4e0d\u58f0\u660e\u7684\u4efb\u4f55\u53d8\u91cf\u90fd\u4f1a\u6210\u4e3a\u4e00\u4e2a\u5168\u5c40\u5bf9\u8c61\u5c5e\u6027\u3002\u53c2\u8003\u4e0b\u9762\u7684\u4ee3\u7801\uff1a<\/p>\n<div class=\"zxx_code\">\n<pre>\nfunction sum(x, y) { \n   <span class=\"cg\">\/\/ \u4e0d\u63a8\u8350\u5199\u6cd5: \u9690\u5f0f\u5168\u5c40\u53d8\u91cf <\/span>\n   result = x + y; \n   return result;\n}\n<\/pre>\n<\/div>\n<p>\u6b64\u6bb5\u4ee3\u7801\u4e2d\u7684<code>result<\/code>\u6ca1\u6709\u58f0\u660e\u3002\u4ee3\u7801\u7167\u6837\u8fd0\u4f5c\u6b63\u5e38\uff0c\u4f46\u5728\u8c03\u7528\u51fd\u6570\u540e\u4f60\u6700\u540e\u7684\u7ed3\u679c\u5c31\u591a\u4e00\u4e2a\u5168\u5c40\u547d\u540d\u7a7a\u95f4\uff0c\u8fd9\u53ef\u4ee5\u662f\u4e00\u4e2a\u95ee\u9898\u7684\u6839\u6e90\u3002<\/p>\n<p>\u7ecf\u9a8c\u6cd5\u5219\u662f\u59cb\u7ec8\u4f7f\u7528var\u58f0\u660e\u53d8\u91cf\uff0c\u6b63\u5982\u6539\u8fdb\u7248\u7684sum()\u51fd\u6570\u6240\u6f14\u793a\u7684\uff1a<\/p>\n<div class=\"zxx_code\">\n<pre>function sum(x, y) {\n   var result = x + y;\n   return result;\n}\n<\/pre>\n<\/div>\n<p>\u53e6\u4e00\u4e2a\u521b\u5efa\u9690\u5f0f\u5168\u5c40\u53d8\u91cf\u7684\u53cd\u4f8b\u5c31\u662f\u4f7f\u7528\u4efb\u52a1\u94fe\u8fdb\u884c\u90e8\u5206var\u58f0\u660e\u3002\u4e0b\u9762\u7684\u7247\u6bb5\u4e2d\uff0c<code>a<\/code>\u662f\u672c\u5730\u53d8\u91cf\u4f46\u662f<code>b<\/code>\u786e\u5b9e\u5168\u5c40\u53d8\u91cf\uff0c\u8fd9\u53ef\u80fd\u4e0d\u662f\u4f60\u5e0c\u671b\u53d1\u751f\u7684\uff1a<\/p>\n<div class=\"zxx_code\">\n<pre>\n<span class=\"cg\">\/\/ \u53cd\u4f8b\uff0c\u52ff\u4f7f\u7528 <\/span>\nfunction foo() {\n   var a = b = 0;\n   <span class=\"cg\">\/\/ ...<\/span>\n}\n<\/pre>\n<\/div>\n<p>\u6b64\u73b0\u8c61\u53d1\u751f\u7684\u539f\u56e0\u5728\u4e8e\u8fd9\u4e2a\u4ece\u53f3\u5230\u5de6\u7684\u8d4b\u503c\uff0c\u9996\u5148\uff0c\u662f\u8d4b\u503c\u8868\u8fbe\u5f0f<code>b = 0<\/code>\uff0c\u6b64\u60c5\u51b5\u4e0bb\u662f\u672a\u58f0\u660e\u7684\u3002\u8fd9\u4e2a\u8868\u8fbe\u5f0f\u7684\u8fd4\u56de\u503c\u662f0\uff0c\u7136\u540e\u8fd9\u4e2a0\u5c31\u5206\u914d\u7ed9\u4e86\u901a\u8fc7var\u5b9a\u4e49\u7684\u8fd9\u4e2a\u5c40\u90e8\u53d8\u91cfa\u3002\u6362\u53e5\u8bdd\u8bf4\uff0c\u5c31\u597d\u6bd4\u4f60\u8f93\u5165\u4e86\uff1a<\/p>\n<div class=\"zxx_code\">\n<pre>var a = (b = 0);<\/pre>\n<\/div>\n<p>\u5982\u679c\u4f60\u5df2\u7ecf\u51c6\u5907\u597d\u58f0\u660e\u53d8\u91cf\uff0c\u4f7f\u7528\u94fe\u5206\u914d\u662f\u6bd4\u8f83\u597d\u7684\u505a\u6cd5\uff0c\u4e0d\u4f1a\u4ea7\u751f\u4efb\u4f55\u610f\u6599\u4e4b\u5916\u7684\u5168\u5c40\u53d8\u91cf\uff0c\u5982\uff1a<\/p>\n<div class=\"zxx_code\">\n<pre>\nfunction foo() {\n   var a, b;\n   <span class=\"cg\">\/\/ ... a = b = 0; \/\/ \u4e24\u4e2a\u5747\u5c40\u90e8\u53d8\u91cf<\/span>\n}\n<\/pre>\n<\/div>\n<blockquote><p>\n\u7136\u800c\uff0c\u53e6\u5916\u4e00\u4e2a\u907f\u514d\u5168\u5c40\u53d8\u91cf\u7684\u539f\u56e0\u662f\u53ef\u79fb\u690d\u6027\u3002\u5982\u679c\u4f60\u60f3\u4f60\u7684\u4ee3\u7801\u5728\u4e0d\u540c\u7684\u73af\u5883\u4e0b\uff08\u4e3b\u673a\u4e0b\uff09\u8fd0\u884c\uff0c\u4f7f\u7528\u5168\u5c40\u53d8\u91cf\u5982\u5c65\u8584\u51b0\uff0c\u56e0\u4e3a\u4f60\u4f1a\u65e0\u610f\u4e2d\u8986\u76d6\u4f60\u6700\u521d\u73af\u5883\u4e0b\u4e0d\u5b58\u5728\u7684\u4e3b\u673a\u5bf9\u8c61\uff08\u6240\u4ee5\u4f60\u539f\u4ee5\u4e3a\u540d\u79f0\u53ef\u4ee5\u653e\u5fc3\u5927\u80c6\u5730\u4f7f\u7528\uff0c\u5b9e\u9645\u4e0a\u5bf9\u4e8e\u6709\u4e9b\u60c5\u51b5\u5e76\u4e0d\u9002\u7528\uff09\u3002\n<\/p><\/blockquote>\n<h3>\u5fd8\u8bb0var\u7684\u526f\u4f5c\u7528(Side Effects When Forgetting var)<\/h3>\n<p>\u9690\u5f0f\u5168\u5c40\u53d8\u91cf\u548c\u660e\u786e\u5b9a\u4e49\u7684\u5168\u5c40\u53d8\u91cf\u95f4\u6709\u4e9b\u5c0f\u7684\u5dee\u5f02\uff0c\u5c31\u662f\u901a\u8fc7<code>delete<\/code>\u64cd\u4f5c\u7b26\u8ba9\u53d8\u91cf\u672a\u5b9a\u4e49\u7684\u80fd\u529b\u3002<\/p>\n<ul id=\"ul\">\n<li>\u901a\u8fc7var\u521b\u5efa\u7684\u5168\u5c40\u53d8\u91cf\uff08\u4efb\u4f55\u51fd\u6570\u4e4b\u5916\u7684\u7a0b\u5e8f\u4e2d\u521b\u5efa\uff09\u662f\u4e0d\u80fd\u88ab\u5220\u9664\u7684\u3002<\/li>\n<li>\u65e0var\u521b\u5efa\u7684\u9690\u5f0f\u5168\u5c40\u53d8\u91cf\uff08\u65e0\u89c6\u662f\u5426\u5728\u51fd\u6570\u4e2d\u521b\u5efa\uff09\u662f\u80fd\u88ab\u5220\u9664\u7684\u3002<\/li>\n<\/ul>\n<p>\u8fd9\u8868\u660e\uff0c\u5728\u6280\u672f\u4e0a\uff0c\u9690\u5f0f\u5168\u5c40\u53d8\u91cf\u5e76\u4e0d\u662f\u771f\u6b63\u7684\u5168\u5c40\u53d8\u91cf\uff0c\u4f46\u5b83\u4eec\u662f\u5168\u5c40\u5bf9\u8c61\u7684\u5c5e\u6027\u3002\u5c5e\u6027\u662f\u53ef\u4ee5\u901a\u8fc7<code>delete<\/code>\u64cd\u4f5c\u7b26\u5220\u9664\u7684\uff0c\u800c\u53d8\u91cf\u662f\u4e0d\u80fd\u7684\uff1a<\/p>\n<div class=\"zxx_code\">\n<pre>\n<span class=\"cg\">\/\/ \u5b9a\u4e49\u4e09\u4e2a\u5168\u5c40\u53d8\u91cf<\/span>\n<span class=\"cdg\">var<\/span> global_var = 1;\nglobal_novar = 2; <span class=\"cg\">\/\/ \u53cd\u9762\u6559\u6750<\/span>\n(<span class=\"cdg\">function<\/span> () {\n   global_fromfunc = 3; <span class=\"cg\">\/\/ \u53cd\u9762\u6559\u6750<\/span>\n}());\n\n<span class=\"cg\">\/\/ \u8bd5\u56fe\u5220\u9664<\/span>\n<span class=\"cdg\">delete<\/span> global_var; <span class=\"cg\">\/\/ false<\/span>\n<span class=\"cdg\">delete<\/span> global_novar; <span class=\"cg\">\/\/ true<\/span>\n<span class=\"cdg\">delete<\/span> global_fromfunc; <span class=\"cg\">\/\/ true<\/span>\n\n<span class=\"cg\">\/\/ \u6d4b\u8bd5\u8be5\u5220\u9664<\/span>\n<span class=\"cdg\">typeof<\/span> global_var; <span class=\"cg\">\/\/ \"number\"<\/span>\n<span class=\"cdg\">typeof<\/span> global_novar; <span class=\"cg\">\/\/ \"undefined\"<\/span>\n<span class=\"cdg\">typeof<\/span> global_fromfunc; <span class=\"cg\">\/\/ \"undefined\"<\/span>\n<\/pre>\n<\/div>\n<p>\u5728ES5\u4e25\u683c\u6a21\u5f0f\u4e0b\uff0c\u672a\u58f0\u660e\u7684\u53d8\u91cf\uff08\u5982\u5728\u524d\u9762\u7684\u4ee3\u7801\u7247\u6bb5\u4e2d\u7684\u4e24\u4e2a\u53cd\u9762\u6559\u6750\uff09\u5de5\u4f5c\u65f6\u4f1a\u629b\u51fa\u4e00\u4e2a\u9519\u8bef\u3002<\/p>\n<h3>\u8bbf\u95ee\u5168\u5c40\u5bf9\u8c61(Access to the Global Object)<\/h3>\n<p>\u5728\u6d4f\u89c8\u5668\u4e2d\uff0c\u5168\u5c40\u5bf9\u8c61\u53ef\u4ee5\u901a\u8fc7<code>window<\/code>\u5c5e\u6027\u5728\u4ee3\u7801\u7684\u4efb\u4f55\u4f4d\u7f6e\u8bbf\u95ee\uff08\u9664\u975e\u4f60\u505a\u4e86\u4e9b\u6bd4\u8f83\u51fa\u683c\u7684\u4e8b\u60c5\uff0c\u50cf\u662f\u58f0\u660e\u4e86\u4e00\u4e2a\u540d\u4e3awindow\u7684\u5c40\u90e8\u53d8\u91cf\uff09\u3002\u4f46\u662f\u5728\u5176\u4ed6\u73af\u5883\u4e0b\uff0c\u8fd9\u4e2a\u65b9\u4fbf\u7684\u5c5e\u6027\u53ef\u80fd\u88ab\u53eb\u505a\u5176\u4ed6\u4ec0\u4e48\u4e1c\u897f\uff08\u751a\u81f3\u5728\u7a0b\u5e8f\u4e2d\u4e0d\u53ef\u7528\uff09\u3002\u5982\u679c\u4f60\u9700\u8981\u5728\u6ca1\u6709\u786c\u7f16\u7801\u7684<code>window<\/code>\u6807\u8bc6\u7b26\u4e0b\u8bbf\u95ee\u5168\u5c40\u5bf9\u8c61\uff0c\u4f60\u53ef\u4ee5\u5728\u4efb\u4f55\u5c42\u7ea7\u7684\u51fd\u6570\u4f5c\u7528\u57df\u4e2d\u505a\u5982\u4e0b\u64cd\u4f5c\uff1a<\/p>\n<div class=\"zxx_code\">\n<pre>\nvar global = (function () {\n   return this;\n}());\n<\/pre>\n<\/div>\n<p>\u8fd9\u79cd\u65b9\u6cd5\u53ef\u4ee5\u968f\u65f6\u83b7\u5f97\u5168\u5c40\u5bf9\u8c61\uff0c\u56e0\u4e3a\u5176\u5728\u51fd\u6570\u4e2d\u88ab\u5f53\u505a\u51fd\u6570\u8c03\u7528\u4e86\uff08\u4e0d\u662f\u901a\u8fc7<code>new<\/code>\u6784\u9020\uff09\uff0c<code>this<\/code>\u603b\u662f\u6307\u5411\u5168\u5c40\u5bf9\u8c61\u3002\u5b9e\u9645\u4e0a\u8fd9\u4e2a\u75c5\u4e0d\u9002\u7528\u4e8eECMAScript 5\u4e25\u683c\u6a21\u5f0f\uff0c\u6240\u4ee5\uff0c\u5728\u4e25\u683c\u6a21\u5f0f\u4e0b\u65f6\uff0c\u4f60\u5fc5\u987b\u91c7\u53d6\u4e0d\u540c\u7684\u5f62\u5f0f\u3002\u4f8b\u5982\uff0c\u4f60\u6b63\u5728\u5f00\u53d1\u4e00\u4e2aJavaScript\u5e93\uff0c\u4f60\u53ef\u4ee5\u5c06\u4f60\u7684\u4ee3\u7801\u5305\u88f9\u5728\u4e00\u4e2a\u5373\u65f6\u51fd\u6570\u4e2d\uff0c\u7136\u540e\u4ece\u5168\u5c40\u4f5c\u7528\u57df\u4e2d\uff0c\u4f20\u9012\u4e00\u4e2a\u5f15\u7528\u6307\u5411this\u4f5c\u4e3a\u4f60\u5373\u65f6\u51fd\u6570\u7684\u53c2\u6570\u3002<\/p>\n<h3>\u5355var\u5f62\u5f0f\uff08Single var Pattern\uff09<\/h3>\n<p>\u5728\u51fd\u6570\u9876\u90e8\u4f7f\u7528\u5355var\u8bed\u53e5\u662f\u6bd4\u8f83\u6709\u7528\u7684\u4e00\u79cd\u5f62\u5f0f\uff0c\u5176\u597d\u5904\u5728\u4e8e\uff1a<\/p>\n<ul id=\"ul\">\n<li>\u63d0\u4f9b\u4e86\u4e00\u4e2a\u5355\u4e00\u7684\u5730\u65b9\u53bb\u5bfb\u627e\u529f\u80fd\u6240\u9700\u8981\u7684\u6240\u6709\u5c40\u90e8\u53d8\u91cf<\/li>\n<li>\u9632\u6b62\u53d8\u91cf\u5728\u5b9a\u4e49\u4e4b\u524d\u4f7f\u7528\u7684\u903b\u8f91\u9519\u8bef<\/li>\n<li>\u5e2e\u52a9\u4f60\u8bb0\u4f4f\u58f0\u660e\u7684\u5168\u5c40\u53d8\u91cf\uff0c\u56e0\u6b64\u8f83\u5c11\u4e86\u5168\u5c40\u53d8\u91cf<span class=\"s ml20\">\/\/zxx:\u6b64\u5904\u6211\u81ea\u5df1\u662f\u6709\u70b9\u6655\u4e4e\u7684&#8230;<\/span><\/li>\n<li>\u5c11\u4ee3\u7801\uff08\u7c7b\u578b\u554a\u4f20\u503c\u554a\u5355\u7ebf\u5b8c\u6210\uff09<\/li>\n<\/ul>\n<p>\u5355var\u5f62\u5f0f\u957f\u5f97\u5c31\u50cf\u4e0b\u9762\u8fd9\u4e2a\u6837\u5b50\uff1a<\/p>\n<div class=\"zxx_code\">\n<pre>\nfunction func() {\n   var a = 1,\n       b = 2,\n       sum = a + b,\n       myobject = {},\n       i,\n       j;\n   <span class=\"cg\">\/\/ function body...<\/span>\n}\n<\/pre>\n<\/div>\n<p>\u60a8\u53ef\u4ee5\u4f7f\u7528\u4e00\u4e2avar\u8bed\u53e5\u58f0\u660e\u591a\u4e2a\u53d8\u91cf\uff0c\u5e76\u4ee5\u9017\u53f7\u5206\u9694\u3002\u50cf\u8fd9\u79cd\u521d\u59cb\u5316\u53d8\u91cf\u540c\u65f6\u521d\u59cb\u5316\u503c\u7684\u505a\u6cd5\u662f\u5f88\u597d\u7684\u3002\u8fd9\u6837\u5b50\u53ef\u4ee5\u9632\u6b62\u903b\u8f91\u9519\u8bef\uff08\u6240\u6709\u672a\u521d\u59cb\u5316\u4f46\u58f0\u660e\u7684\u53d8\u91cf\u7684\u521d\u59cb\u503c\u662f<code>undefined<\/code>\uff09\u548c\u589e\u52a0\u4ee3\u7801\u7684\u53ef\u8bfb\u6027\u3002\u5728\u4f60\u770b\u5230\u4ee3\u7801\u540e\uff0c\u4f60\u53ef\u4ee5\u6839\u636e\u521d\u59cb\u5316\u7684\u503c\u77e5\u9053\u8fd9\u4e9b\u53d8\u91cf\u5927\u81f4\u7684\u7528\u9014\uff0c\u4f8b\u5982\u662f\u8981\u5f53\u4f5c\u5bf9\u8c61\u5462\u8fd8\u662f\u5f53\u4f5c\u6574\u6570\u6765\u4f7f\u3002<\/p>\n<p>\u4f60\u4e5f\u53ef\u4ee5\u5728\u58f0\u660e\u7684\u65f6\u5019\u505a\u4e00\u4e9b\u5b9e\u9645\u7684\u5de5\u4f5c\uff0c\u4f8b\u5982\u524d\u9762\u4ee3\u7801\u4e2d\u7684<code>sum = a + b<\/code>\u8fd9\u4e2a\u60c5\u51b5\uff0c\u53e6\u5916\u4e00\u4e2a\u4f8b\u5b50\u5c31\u662f\u5f53\u4f60\u4f7f\u7528DOM\uff08\u6587\u6863\u5bf9\u8c61\u6a21\u578b\uff09\u5f15\u7528\u65f6\uff0c\u4f60\u53ef\u4ee5\u4f7f\u7528\u5355\u4e00\u7684var\u628aDOM\u5f15\u7528\u4e00\u8d77\u6307\u5b9a\u4e3a\u5c40\u90e8\u53d8\u91cf\uff0c\u5c31\u5982\u4e0b\u9762\u4ee3\u7801\u6240\u793a\u7684\uff1a<\/p>\n<div class=\"zxx_code\">\n<pre>\nfunction updateElement() {\n   var el = document.getElementById(\"result\"),\n       style = el.style;\n   <span class=\"cg\">\/\/ \u4f7f\u7528el\u548cstyle\u5e72\u70b9\u5176\u4ed6\u4ec0\u4e48\u4e8b...<\/span>\n}\n<\/pre>\n<\/div>\n<h3>\u9884\u89e3\u6790\uff1avar\u6563\u5e03\u7684\u95ee\u9898(Hoisting: A Problem with Scattered vars)<\/h3>\n<p>JavaScript\u4e2d\uff0c\u4f60\u53ef\u4ee5\u5728\u51fd\u6570\u7684\u4efb\u4f55\u4f4d\u7f6e\u58f0\u660e\u591a\u4e2avar\u8bed\u53e5\uff0c\u5e76\u4e14\u5b83\u4eec\u5c31\u597d\u50cf\u662f\u5728\u51fd\u6570\u9876\u90e8\u58f0\u660e\u4e00\u6837\u53d1\u6325\u4f5c\u7528\uff0c\u8fd9\u79cd\u884c\u4e3a\u79f0\u4e3ahoisting\uff08\u60ac\u7f6e\/\u7f6e\u9876\u89e3\u6790\/\u9884\u89e3\u6790\uff09\u3002\u5f53\u4f60\u4f7f\u7528\u4e86\u4e00\u4e2a\u53d8\u91cf\uff0c\u7136\u540e\u4e0d\u4e45\u5728\u51fd\u6570\u4e2d\u53c8\u91cd\u65b0\u58f0\u660e\u7684\u8bdd\uff0c\u5c31\u53ef\u80fd\u4ea7\u751f\u903b\u8f91\u9519\u8bef\u3002\u5bf9\u4e8eJavaScript\uff0c\u53ea\u8981\u4f60\u7684\u53d8\u91cf\u662f\u5728\u540c\u4e00\u4e2a\u4f5c\u7528\u57df\u4e2d\uff08\u540c\u4e00\u51fd\u6570\uff09\uff0c\u5b83\u90fd\u88ab\u5f53\u505a\u662f\u58f0\u660e\u7684\uff0c\u5373\u4f7f\u662f\u5b83\u5728var\u58f0\u660e\u524d\u4f7f\u7528\u7684\u65f6\u5019\u3002\u770b\u4e0b\u9762\u8fd9\u4e2a\u4f8b\u5b50\uff1a<\/p>\n<div class=\"zxx_code\">\n<pre>\n<span class=\"cg\">\/\/ \u53cd\u4f8b<\/span>\nmyname = \"global\"; <span class=\"cg\">\/\/ \u5168\u5c40\u53d8\u91cf<\/span>\nfunction func() {\n    alert(myname); <span class=\"cg\">\/\/ \"undefined\"<\/span>\n    var myname = \"local\";\n    alert(myname); <span class=\"cg\">\/\/ \"local\"<\/span>\n}\nfunc();\n<\/pre>\n<\/div>\n<p>\u5728\u8fd9\u4e2a\u4f8b\u5b50\u4e2d\uff0c\u4f60\u53ef\u80fd\u4f1a\u4ee5\u4e3a\u7b2c\u4e00\u4e2aalert\u5f39\u51fa\u7684\u662f&#8221;global&#8221;\uff0c\u7b2c\u4e8c\u4e2a\u5f39\u51fa&#8221;loacl&#8221;\u3002\u8fd9\u79cd\u671f\u8bb8\u662f\u53ef\u4ee5\u7406\u89e3\u7684\uff0c\u56e0\u4e3a\u5728\u7b2c\u4e00\u4e2aalert\u7684\u65f6\u5019\uff0cmyname\u672a\u58f0\u660e\uff0c\u6b64\u65f6\u51fd\u6570\u80af\u5b9a\u5f88\u81ea\u7136\u800c\u7136\u5730\u770b\u5168\u5c40\u53d8\u91cfmyname\uff0c\u4f46\u662f\uff0c\u5b9e\u9645\u4e0a\u5e76\u4e0d\u662f\u8fd9\u4e48\u5de5\u4f5c\u7684\u3002\u7b2c\u4e00\u4e2aalert\u4f1a\u5f39\u51fa&#8221;undefined&#8221;\u662f\u56e0\u4e3amyname\u88ab\u5f53\u505a\u4e86\u51fd\u6570\u7684\u5c40\u90e8\u53d8\u91cf\uff08\u5c3d\u7ba1\u662f\u4e4b\u540e\u58f0\u660e\u7684\uff09\uff0c\u6240\u6709\u7684\u53d8\u91cf\u58f0\u660e\u5f53\u88ab\u60ac\u7f6e\u5230\u51fd\u6570\u7684\u9876\u90e8\u4e86\u3002\u56e0\u6b64\uff0c\u4e3a\u4e86\u907f\u514d\u8fd9\u79cd\u6df7\u4e71\uff0c\u6700\u597d\u662f\u9884\u5148\u58f0\u660e\u4f60\u60f3\u4f7f\u7528\u7684\u5168\u90e8\u53d8\u91cf\u3002<\/p>\n<p>\u4e0a\u9762\u7684\u4ee3\u7801\u7247\u6bb5\u6267\u884c\u7684\u884c\u4e3a\u53ef\u80fd\u5c31\u50cf\u4e0b\u9762\u8fd9\u6837\uff1a<\/p>\n<div class=\"zxx_code\">\n<pre>\nmyname = \"global\"; \/\/ global variable\nfunction func() {\n   var myname; <span class=\"cg\">\/\/ \u7b49\u540c\u4e8e -> var myname = undefined;<\/span>\n   alert(myname); <span class=\"cg\">\/\/ \"undefined\"<\/span>\n   myname = \"local\";\n   alert(myname); <span class=\"cg\">\/\/ \"local\"<\/span>}\nfunc();\n<\/pre>\n<\/div>\n<p><span class=\"s\">\/\/zxx:\u5173\u4e8eJavaScript\u7684\u7f6e\u9876\u89e3\u6790\uff0c\u6211\u4e0a\u5468\u4e13\u95e8\u7ffb\u8bd1\u4e86\u7bc7\u6587\u7ae0\uff0c\u60a8\u6709\u5174\u8da3\u53ef\u4ee5\u770b\u770b\uff1a\u201c<a title=\"\u7ffb\u8bd1 &ndash; \u89e3\u91caJavaScript\u7684\u7f6e\u9876\u89e3\u6790\" href=\"http:\/\/www.zhangxinxu.com\/wordpress\/?p=1162\">\u7ffb\u8bd1 &ndash; \u89e3\u91caJavaScript\u7684\u7f6e\u9876\u89e3\u6790<\/a>\u201d\u3002<\/span><\/p>\n<blockquote><p>\n\u4e3a\u4e86\u5b8c\u6574\uff0c\u6211\u4eec\u518d\u63d0\u4e00\u63d0\u6267\u884c\u5c42\u9762\u7684\u7a0d\u5fae\u590d\u6742\u70b9\u7684\u4e1c\u897f\u3002\u4ee3\u7801\u5904\u7406\u5206\u4e24\u4e2a\u9636\u6bb5\uff0c\u7b2c\u4e00\u9636\u6bb5\u662f\u53d8\u91cf\uff0c\u51fd\u6570\u58f0\u660e\uff0c\u4ee5\u53ca\u6b63\u5e38\u683c\u5f0f\u7684\u53c2\u6570\u521b\u5efa\uff0c\u8fd9\u662f\u4e00\u4e2a\u89e3\u6790\u548c\u8fdb\u5165\u4e0a\u4e0b\u6587\u7684\u9636\u6bb5\u3002\u7b2c\u4e8c\u4e2a\u9636\u6bb5\u662f\u4ee3\u7801\u6267\u884c\uff0c\u51fd\u6570\u8868\u8fbe\u5f0f\u548c\u4e0d\u5408\u683c\u7684\u6807\u8bc6\u7b26\uff08\u4e3a\u58f0\u660e\u7684\u53d8\u91cf\uff09\u88ab\u521b\u5efa\u3002\u4f46\u662f\uff0c\u51fa\u4e8e\u5b9e\u7528\u7684\u76ee\u7684\uff0c\u6211\u4eec\u5c31\u91c7\u7528\u4e86&#8221;hoisting&#8221;\u8fd9\u4e2a\u6982\u5ff5\uff0c\u8fd9\u79cdECMAScript\u6807\u51c6\u4e2d\u5e76\u672a\u5b9a\u4e49\uff0c\u901a\u5e38\u7528\u6765\u63cf\u8ff0\u884c\u4e3a\u3002\n<\/p><\/blockquote>\n<h3>for\u5faa\u73af(for Loops)<\/h3>\n<p>\u5728<code>for<\/code>\u5faa\u73af\u4e2d\uff0c\u4f60\u53ef\u4ee5\u5faa\u73af\u53d6\u5f97\u6570\u7ec4\u6216\u662f\u6570\u7ec4\u7c7b\u4f3c\u5bf9\u8c61\u7684\u503c\uff0c\u8b6c\u5982<code>arguments<\/code>\u548c<code>HTMLCollection<\/code>\u5bf9\u8c61\u3002\u901a\u5e38\u7684\u5faa\u73af\u5f62\u5f0f\u5982\u4e0b\uff1a<\/p>\n<div class=\"zxx_code\">\n<pre>\n<span class=\"cg\">\/\/ \u6b21\u4f73\u7684\u5faa\u73af<\/span>\nfor (var i = 0; i < myarray.length; i++) {\n   <span class=\"cg\">\/\/ \u4f7f\u7528myarray[i]\u505a\u70b9\u4ec0\u4e48<\/span>\n}\n<\/pre>\n<\/div>\n<p>\u8fd9\u79cd\u5f62\u5f0f\u7684\u5faa\u73af\u7684\u4e0d\u8db3\u5728\u4e8e\u6bcf\u6b21\u5faa\u73af\u7684\u65f6\u5019\u6570\u7ec4\u7684\u957f\u5ea6\u90fd\u8981\u53bb\u83b7\u53d6\u4e0b\u3002\u8fd9\u56de\u964d\u4f4e\u4f60\u7684\u4ee3\u7801\uff0c\u5c24\u5176\u5f53<code>myarray<\/code>\u4e0d\u662f\u6570\u7ec4\uff0c\u800c\u662f\u4e00\u4e2a<code>HTMLCollection<\/code>\u5bf9\u8c61\u7684\u65f6\u5019\u3002<\/p>\n<p><code>HTMLCollections<\/code>\u6307\u7684\u662fDOM\u65b9\u6cd5\u8fd4\u56de\u7684\u5bf9\u8c61\uff0c\u4f8b\u5982\uff1a<\/p>\n<div class=\"zxx_code\">\n<pre>\ndocument.getElementsByName()\ndocument.getElementsByClassName()\ndocument.getElementsByTagName()\n<\/pre>\n<\/div>\n<p>\u8fd8\u6709\u5176\u4ed6\u4e00\u4e9b<code>HTMLCollections<\/code>\uff0c\u8fd9\u4e9b\u662f\u5728DOM\u6807\u51c6\u4e4b\u524d\u5f15\u8fdb\u5e76\u4e14\u73b0\u5728\u8fd8\u5728\u4f7f\u7528\u7684\u3002\u6709\uff1a<\/p>\n<div class=\"zxx_code\">\n<pre>\ndocument.images: \u9875\u9762\u4e0a\u6240\u6709\u7684\u56fe\u7247\u5143\u7d20\ndocument.links : \u6240\u6709a\u6807\u7b7e\u5143\u7d20\ndocument.forms : \u6240\u6709\u8868\u5355\ndocument.forms[0].elements : \u9875\u9762\u4e0a\u7b2c\u4e00\u4e2a\u8868\u5355\u4e2d\u7684\u6240\u6709\u57df\n<\/pre>\n<\/div>\n<p>\u96c6\u5408\u7684\u9ebb\u70e6\u5728\u4e8e\u5b83\u4eec\u5b9e\u65f6\u67e5\u8be2\u57fa\u672c\u6587\u6863\uff08HTML\u9875\u9762\uff09\u3002\u8fd9\u610f\u5473\u7740\u6bcf\u6b21\u4f60\u8bbf\u95ee\u4efb\u4f55\u96c6\u5408\u7684\u957f\u5ea6\uff0c\u4f60\u8981\u5b9e\u65f6\u67e5\u8be2DOM\uff0c\u800cDOM\u64cd\u4f5c\u4e00\u822c\u90fd\u662f\u6bd4\u8f83\u6602\u8d35\u7684\u3002<\/p>\n<p>\u8fd9\u5c31\u662f\u4e3a\u4ec0\u4e48\u5f53\u4f60\u5faa\u73af\u83b7\u53d6\u503c\u65f6\uff0c\u7f13\u5b58\u6570\u7ec4(\u6216\u96c6\u5408)\u7684\u957f\u5ea6\u662f\u6bd4\u8f83\u597d\u7684\u5f62\u5f0f\uff0c\u6b63\u5982\u4e0b\u9762\u4ee3\u7801\u663e\u793a\u7684\uff1a<\/p>\n<div class=\"zxx_code\">\n<pre>\nfor (var i = 0, max = myarray.length; i < max; i++) {\n   <span class=\"cg\">\/\/ \u4f7f\u7528myarray[i]\u505a\u70b9\u4ec0\u4e48<\/span>\n}\n<\/pre>\n<\/div>\n<p>\u8fd9\u6837\uff0c\u5728\u8fd9\u4e2a\u5faa\u73af\u8fc7\u7a0b\u4e2d\uff0c\u4f60\u53ea\u68c0\u7d22\u4e86\u4e00\u6b21\u957f\u5ea6\u503c\u3002<\/p>\n<p>\u5728\u6240\u6709\u6d4f\u89c8\u5668\u4e0b\uff0c\u5faa\u73af\u83b7\u53d6\u5185\u5bb9\u65f6\u7f13\u5b58<code>HTMLCollections<\/code>\u7684\u957f\u5ea6\u662f\u66f4\u5feb\u7684\uff0c2\u500d(Safari3)\u5230190\u500d(IE7)\u4e4b\u95f4\u3002<span class=\"s\">\/\/zxx:\u6b64\u6570\u636e\u8c8c\u4f3c\u5f88\u8001\uff0c\u4ec5\u4f9b\u53c2\u8003<\/span><\/p>\n<p>\u6ce8\u610f\u5230\uff0c\u5f53\u4f60\u660e\u786e\u60f3\u8981\u4fee\u6539\u5faa\u73af\u4e2d\u7684\u96c6\u5408\u7684\u65f6\u5019\uff08\u4f8b\u5982\uff0c\u6dfb\u52a0\u66f4\u591a\u7684DOM\u5143\u7d20\uff09\uff0c\u4f60\u53ef\u80fd\u66f4\u559c\u6b22\u957f\u5ea6\u66f4\u65b0\u800c\u4e0d\u662f\u5e38\u91cf\u3002<\/p>\n<p>\u4f34\u968f\u7740\u5355var\u5f62\u5f0f\uff0c\u4f60\u53ef\u4ee5\u628a\u53d8\u91cf\u4ece\u5faa\u73af\u4e2d\u63d0\u51fa\u6765\uff0c\u5c31\u50cf\u4e0b\u9762\u8fd9\u6837\uff1a<\/p>\n<div class=\"zxx_code\">\n<pre>\nfunction looper() {\n   var i = 0,\n        max,\n        myarray = [];\n   <span class=\"cg\">\/\/ ...<\/span>\n   for (i = 0, max = myarray.length; i < max; i++) {\n      <span class=\"cg\">\/\/ \u4f7f\u7528myarray[i]\u505a\u70b9\u4ec0\u4e48<\/span>\n   }\n}\n<\/pre>\n<\/div>\n<p>\u8fd9\u79cd\u5f62\u5f0f\u5177\u6709\u4e00\u81f4\u6027\u7684\u597d\u5904\uff0c\u56e0\u4e3a\u4f60\u575a\u6301\u4e86\u5355\u4e00var\u5f62\u5f0f\u3002\u4e0d\u8db3\u5728\u4e8e\u5f53\u91cd\u6784\u4ee3\u7801\u7684\u65f6\u5019\uff0c\u590d\u5236\u548c\u7c98\u8d34\u6574\u4e2a\u5faa\u73af\u6709\u70b9\u56f0\u96be\u3002\u4f8b\u5982\uff0c\u4f60\u4ece\u4e00\u4e2a\u51fd\u6570\u590d\u5236\u4e86\u4e00\u4e2a\u5faa\u73af\u5230\u53e6\u4e00\u4e2a\u51fd\u6570\uff0c\u4f60\u4e0d\u5f97\u4e0d\u53bb\u786e\u5b9a\u4f60\u80fd\u591f\u628a<code>i<\/code>\u548c<code>max<\/code>\u5f15\u5165\u65b0\u7684\u51fd\u6570\uff08\u5982\u679c\u5728\u8fd9\u91cc\u6ca1\u6709\u7528\u7684\u8bdd\uff0c\u5f88\u6709\u53ef\u80fd\u4f60\u8981\u4ece\u539f\u51fd\u6570\u4e2d\u628a\u5b83\u4eec\u5220\u6389\uff09\u3002<\/p>\n<p>\u6700\u540e\u4e00\u4e2a\u9700\u8981\u5bf9\u5faa\u73af\u8fdb\u884c\u8c03\u6574\u7684\u662f\u4f7f\u7528\u4e0b\u9762\u8868\u8fbe\u5f0f\u4e4b\u4e00\u6765\u66ff\u6362<code>i++<\/code>\u3002<\/p>\n<div class=\"zxx_code\">\n<pre>\ni = i + 1  \ni += 1 \n<\/pre>\n<\/div>\n<p>JSLint\u63d0\u793a\u60a8\u8fd9\u6837\u505a\uff0c\u539f\u56e0\u662f<code>++<\/code>\u548c<code>&ndash;-<\/code>\u4fc3\u8fdb\u4e86\u201c\u8fc7\u5206\u68d8\u624b(excessive trickiness)\u201d\u3002<span class=\"s\">\/\/zxx:\u8fd9\u91cc\u6bd4\u8f83\u96be\u7ffb\u8bd1\uff0c\u6211\u60f3\u672c\u610f\u5e94\u8be5\u662f\u8ba9\u4ee3\u7801\u53d8\u5f97\u66f4\u52a0\u7684\u68d8\u624b<\/span><br \/>\u5982\u679c\u4f60\u76f4\u63a5\u65e0\u89c6\u5b83\uff0cJSLint\u7684<code>plusplus<\/code>\u9009\u9879\u4f1a\u662f<code>false<\/code>\uff08\u9ed8\u8ba4\u662fdefault\uff09\u3002<\/p>\n<p>\u8fd8\u6709\u4e24\u79cd\u53d8\u5316\u7684\u5f62\u5f0f\uff0c\u5176\u53c8\u6709\u4e86\u4e9b\u5fae\u6539\u8fdb\uff0c\u56e0\u4e3a\uff1a<\/p>\n<ul id=\"ul\">\n<li>\u5c11\u4e86\u4e00\u4e2a\u53d8\u91cf(\u65e0max)<\/li>\n<li>\u5411\u4e0b\u6570\u52300\uff0c\u901a\u5e38\u66f4\u5feb\uff0c\u56e0\u4e3a\u548c0\u505a\u6bd4\u8f83\u8981\u6bd4\u548c\u6570\u7ec4\u957f\u5ea6\u6216\u662f\u5176\u4ed6\u4e0d\u662f0\u7684\u4e1c\u897f\u4f5c\u6bd4\u8f83\u66f4\u6709\u6548\u7387<\/li>\n<\/ul>\n<p>\u7b2c\u4e00\u79cd\u53d8\u5316\u7684\u5f62\u5f0f\uff1a<\/p>\n<div class=\"zxx_code\">\n<pre>\nvar i, myarray = [];\nfor (i = myarray.length; i&ndash;-;) {\n   <span class=\"cg\">\/\/ \u4f7f\u7528myarray[i]\u505a\u70b9\u4ec0\u4e48<\/span>\n}\n<\/pre>\n<\/div>\n<p>\u7b2c\u4e8c\u79cd\u4f7f\u7528<code>while<\/code>\u5faa\u73af\uff1a<\/p>\n<div class=\"zxx_code\">\n<pre>\nvar myarray = [],\n    i = myarray.length;\nwhile (i&ndash;-) {\n   <span class=\"cg\">\/\/ \u4f7f\u7528myarray[i]\u505a\u70b9\u4ec0\u4e48<\/span>\n}\n<\/pre>\n<\/div>\n<p>\u8fd9\u4e9b\u5c0f\u7684\u6539\u8fdb\u53ea\u4f53\u73b0\u5728\u6027\u80fd\u4e0a\uff0c\u6b64\u5916JSLint\u4f1a\u5bf9\u4f7f\u7528i&ndash;-\u52a0\u4ee5\u62b1\u6028\u3002<\/p>\n<h3>for-in\u5faa\u73af(for-in Loops)<\/h3>\n<p><code>for-in<\/code>\u5faa\u73af\u5e94\u8be5\u7528\u5728\u975e\u6570\u7ec4\u5bf9\u8c61\u7684\u904d\u5386\u4e0a\uff0c\u4f7f\u7528<code>for-in<\/code>\u8fdb\u884c\u5faa\u73af\u4e5f\u88ab\u79f0\u4e3a\u201c\u679a\u4e3e\u201d\u3002<\/p>\n<p>\u4ece\u6280\u672f\u4e0a\u5c06\uff0c\u4f60\u53ef\u4ee5\u4f7f\u7528<code>for-in<\/code>\u5faa\u73af\u6570\u7ec4\uff08\u56e0\u4e3aJavaScript\u4e2d\u6570\u7ec4\u4e5f\u662f\u5bf9\u8c61\uff09\uff0c\u4f46\u8fd9\u662f\u4e0d\u63a8\u8350\u7684\u3002\u56e0\u4e3a\u5982\u679c\u6570\u7ec4\u5bf9\u8c61\u5df2\u88ab\u81ea\u5b9a\u4e49\u7684\u529f\u80fd\u589e\u5f3a\uff0c\u5c31\u53ef\u80fd\u53d1\u751f\u903b\u8f91\u9519\u8bef\u3002\u53e6\u5916\uff0c\u5728for-in\u4e2d\uff0c\u5c5e\u6027\u5217\u8868\u7684\u987a\u5e8f\uff08\u5e8f\u5217\uff09\u662f\u4e0d\u80fd\u4fdd\u8bc1\u7684\u3002\u6240\u4ee5\u6700\u597d\u6570\u7ec4\u4f7f\u7528\u6b63\u5e38\u7684for\u5faa\u73af\uff0c\u5bf9\u8c61\u4f7f\u7528for-in\u5faa\u73af\u3002<\/p>\n<p>\u6709\u4e2a\u5f88\u91cd\u8981\u7684<code>hasOwnProperty()<\/code>\u65b9\u6cd5\uff0c\u5f53\u904d\u5386\u5bf9\u8c61\u5c5e\u6027\u7684\u65f6\u5019\u53ef\u4ee5\u8fc7\u6ee4\u6389\u4ece\u539f\u578b\u94fe\u4e0a\u4e0b\u6765\u7684\u5c5e\u6027\u3002<\/p>\n<p>\u601d\u8003\u4e0b\u9762\u4e00\u6bb5\u4ee3\u7801\uff1a<\/p>\n<div class=\"zxx_code\">\n<pre>\n<span class=\"cg\">\/\/ \u5bf9\u8c61<\/span>\nvar man = {\n   hands: 2,\n   legs: 2,\n   heads: 1\n};\n\n<span class=\"cg\">\/\/ \u5728\u4ee3\u7801\u7684\u67d0\u4e2a\u5730\u65b9<\/span>\n<span class=\"cg\">\/\/ \u4e00\u4e2a\u65b9\u6cd5\u6dfb\u52a0\u7ed9\u4e86\u6240\u6709\u5bf9\u8c61<\/span>\nif (typeof Object.prototype.clone === \"undefined\") {\n   Object.prototype.clone = function () {};\n}\n<\/pre>\n<\/div>\n<p>\u5728\u8fd9\u4e2a\u4f8b\u5b50\u4e2d\uff0c\u6211\u4eec\u6709\u4e00\u4e2a\u4f7f\u7528\u5bf9\u8c61\u5b57\u9762\u91cf\u5b9a\u4e49\u7684\u540d\u53ebman\u7684\u5bf9\u8c61\u3002\u5728man\u5b9a\u4e49\u5b8c\u6210\u540e\u7684\u67d0\u4e2a\u5730\u65b9\uff0c\u5728\u5bf9\u8c61\u539f\u578b\u4e0a\u589e\u52a0\u4e86\u4e00\u4e2a\u5f88\u6709\u7528\u7684\u540d\u53ebclone()\u7684\u65b9\u6cd5\u3002\u6b64\u539f\u578b\u94fe\u662f\u5b9e\u65f6\u7684\uff0c\u8fd9\u5c31\u610f\u5473\u7740\u6240\u6709\u7684\u5bf9\u8c61\u81ea\u52a8\u53ef\u4ee5\u8bbf\u95ee\u65b0\u7684\u65b9\u6cd5\u3002\u4e3a\u4e86\u907f\u514d\u679a\u4e3eman\u7684\u65f6\u5019\u51fa\u73b0clone()\u65b9\u6cd5\uff0c\u4f60\u9700\u8981\u5e94\u7528<code>hasOwnProperty()<\/code>\u65b9\u6cd5\u8fc7\u6ee4\u539f\u578b\u5c5e\u6027\u3002\u5982\u679c\u4e0d\u505a\u8fc7\u6ee4\uff0c\u4f1a\u5bfc\u81f4clone()\u51fd\u6570\u663e\u793a\u51fa\u6765\uff0c\u5728\u5927\u591a\u6570\u60c5\u51b5\u4e0b\u8fd9\u662f\u4e0d\u5e0c\u671b\u51fa\u73b0\u7684\u3002<\/p>\n<div class=\"zxx_code\">\n<pre>\n<span class=\"cg\">\/\/ 1.\n\/\/ for-in \u5faa\u73af<\/span>\nfor (var i in man) {\n   if (man.hasOwnProperty(i)) { <span class=\"cg\">\/\/ \u8fc7\u6ee4<\/span>\n      console.log(i, \":\", man[i]);\n   }\n}\n<span class=\"cg\">\/* \u63a7\u5236\u53f0\u663e\u793a\u7ed3\u679c\nhands : 2\nlegs : 2\nheads : 1\n*\/<\/span>\n<span class=\"cg\">\/\/ 2.\n\/\/ \u53cd\u9762\u4f8b\u5b50:\n\/\/ for-in loop without checking hasOwnProperty()<\/span>\nfor (var i in man) {\n   console.log(i, \":\", man[i]);\n}\n<span class=\"cg\">\/*\n\u63a7\u5236\u53f0\u663e\u793a\u7ed3\u679c\nhands : 2\nlegs : 2\nheads : 1\nclone: function()\n*\/<\/span>\n<\/pre>\n<\/div>\n<p>\u53e6\u5916\u4e00\u79cd\u4f7f\u7528<code>hasOwnProperty()<\/code>\u7684\u5f62\u5f0f\u662f\u53d6\u6d88Object.prototype\u4e0a\u7684\u65b9\u6cd5\u3002\u50cf\u662f\uff1a<\/p>\n<div class=\"zxx_code\">\n<pre>\nfor (var i in man) {\n   if (Object.prototype.hasOwnProperty.call(man, i)) { <span class=\"cg\">\/\/ \u8fc7\u6ee4<\/span>\n      console.log(i, \":\", man[i]);\n   }\n}\n<\/pre>\n<\/div>\n<p>\u5176\u597d\u5904\u5728\u4e8e\u5728man\u5bf9\u8c61\u91cd\u65b0\u5b9a\u4e49hasOwnProperty\u60c5\u51b5\u4e0b\u907f\u514d\u547d\u540d\u51b2\u7a81\u3002\u4e5f\u907f\u514d\u4e86\u957f\u5c5e\u6027\u67e5\u627e\u5bf9\u8c61\u7684\u6240\u6709\u65b9\u6cd5\uff0c\u4f60\u53ef\u4ee5\u4f7f\u7528\u5c40\u90e8\u53d8\u91cf\u201c\u7f13\u5b58\u201d\u5b83\u3002<\/p>\n<div class=\"zxx_code\">\n<pre>\nvar i, hasOwn = Object.prototype.hasOwnProperty;\nfor (i in man) {\n    if (hasOwn.call(man, i)) { <span class=\"cg\">\/\/ \u8fc7\u6ee4<\/span>\n        console.log(i, \":\", man[i]);\n    }\n}\n<\/pre>\n<\/div>\n<blockquote><p>\n\u4e25\u683c\u6765\u8bf4\uff0c\u4e0d\u4f7f\u7528<code>hasOwnProperty()<\/code>\u5e76\u4e0d\u662f\u4e00\u4e2a\u9519\u8bef\u3002\u6839\u636e\u4efb\u52a1\u4ee5\u53ca\u4f60\u5bf9\u4ee3\u7801\u7684\u81ea\u4fe1\u7a0b\u5ea6\uff0c\u4f60\u53ef\u4ee5\u8df3\u8fc7\u5b83\u4ee5\u63d0\u9ad8\u4e9b\u8bb8\u7684\u5faa\u73af\u901f\u5ea6\u3002\u4f46\u662f\u5f53\u4f60\u5bf9\u5f53\u524d\u5bf9\u8c61\u5185\u5bb9\uff08\u548c\u5176\u539f\u578b\u94fe\uff09\u4e0d\u786e\u5b9a\u7684\u65f6\u5019\uff0c\u6dfb\u52a0<code>hasOwnProperty()<\/code>\u66f4\u52a0\u4fdd\u9669\u4e9b\u3002\n<\/p><\/blockquote>\n<p>\u683c\u5f0f\u5316\u7684\u53d8\u5316\uff08\u901a\u4e0d\u8fc7JSLint\uff09\u4f1a\u76f4\u63a5\u5ffd\u7565\u6389\u82b1\u62ec\u53f7\uff0c\u628aif\u8bed\u53e5\u653e\u5230\u540c\u4e00\u884c\u4e0a\u3002\u5176\u4f18\u70b9\u5728\u4e8e\u5faa\u73af\u8bed\u53e5\u8bfb\u8d77\u6765\u5c31\u50cf\u4e00\u4e2a\u5b8c\u6574\u7684\u60f3\u6cd5\uff08\u6bcf\u4e2a\u5143\u7d20\u90fd\u6709\u4e00\u4e2a\u81ea\u5df1\u7684\u5c5e\u6027&#8221;X&#8221;\uff0c\u4f7f\u7528&#8221;X&#8221;\u5e72\u70b9\u4ec0\u4e48\uff09\uff1a<\/p>\n<div class=\"zxx_code\">\n<pre>\n<span class=\"cg\">\/\/ \u8b66\u544a\uff1a \u901a\u4e0d\u8fc7JSLint\u68c0\u6d4b<\/span>\nvar i, hasOwn = Object.prototype.hasOwnProperty;\nfor (i in man) if (hasOwn.call(man, i)) { <span class=\"cg\">\/\/ \u8fc7\u6ee4<\/span>\n    console.log(i, \":\", man[i]);\n}\n<\/pre>\n<\/div>\n<h3>\uff08\u4e0d\uff09\u6269\u5c55\u5185\u7f6e\u539f\u578b((Not) Augmenting Built-in Prototypes)<\/h3>\n<p>\u6269\u589e\u6784\u9020\u51fd\u6570\u7684prototype\u5c5e\u6027\u662f\u4e2a\u5f88\u5f3a\u5927\u7684\u589e\u52a0\u529f\u80fd\u7684\u65b9\u6cd5\uff0c\u4f46\u6709\u65f6\u5019\u5b83\u592a\u5f3a\u5927\u4e86\u3002<\/p>\n<p>\u589e\u52a0\u5185\u7f6e\u7684\u6784\u9020\u51fd\u6570\u539f\u578b\uff08\u5982Object(), Array(), \u6216Function()\uff09\u633a\u8bf1\u4eba\u7684\uff0c\u4f46\u662f\u8fd9\u4e25\u91cd\u964d\u4f4e\u4e86\u53ef\u7ef4\u62a4\u6027\uff0c\u56e0\u4e3a\u5b83\u8ba9\u4f60\u7684\u4ee3\u7801\u53d8\u5f97\u96be\u4ee5\u9884\u6d4b\u3002\u4f7f\u7528\u4f60\u4ee3\u7801\u7684\u5176\u4ed6\u5f00\u53d1\u4eba\u5458\u5f88\u53ef\u80fd\u66f4\u671f\u671b\u4f7f\u7528\u5185\u7f6e\u7684JavaScript\u65b9\u6cd5\u6765\u6301\u7eed\u4e0d\u65ad\u5730\u5de5\u4f5c\uff0c\u800c\u4e0d\u662f\u4f60\u53e6\u52a0\u7684\u65b9\u6cd5\u3002<\/p>\n<p>\u53e6\u5916\uff0c\u5c5e\u6027\u6dfb\u52a0\u5230\u539f\u578b\u4e2d\uff0c\u53ef\u80fd\u4f1a\u5bfc\u81f4\u4e0d\u4f7f\u7528hasOwnProperty\u5c5e\u6027\u65f6\u5728\u5faa\u73af\u4e2d\u663e\u793a\u51fa\u6765\uff0c\u8fd9\u4f1a\u9020\u6210\u6df7\u4e71\u3002<\/p>\n<p>\u56e0\u6b64\uff0c\u4e0d\u589e\u52a0\u5185\u7f6e\u539f\u578b\u662f\u6700\u597d\u7684\u3002\u4f60\u53ef\u4ee5\u6307\u5b9a\u4e00\u4e2a\u89c4\u5219\uff0c\u4ec5\u5f53\u4e0b\u9762\u7684\u6761\u4ef6\u5747\u6ee1\u8db3\u65f6\u4f8b\u5916\uff1a<\/p>\n<ul id=\"ul\">\n<li>\u53ef\u4ee5\u9884\u671f\u5c06\u6765\u7684ECMAScript\u7248\u672c\u6216\u662fJavaScript\u5b9e\u73b0\u5c06\u4e00\u76f4\u5c06\u6b64\u529f\u80fd\u5f53\u4f5c\u5185\u7f6e\u65b9\u6cd5\u6765\u5b9e\u73b0\u3002\u4f8b\u5982\uff0c\u4f60\u53ef\u4ee5\u6dfb\u52a0ECMAScript 5\u4e2d\u63cf\u8ff0\u7684\u65b9\u6cd5\uff0c\u4e00\u76f4\u5230\u5404\u4e2a\u6d4f\u89c8\u5668\u90fd\u8fce\u5934\u8d76\u4e0a\u3002\u8fd9\u79cd\u60c5\u51b5\u4e0b\uff0c\u4f60\u53ea\u662f\u63d0\u524d\u5b9a\u4e49\u4e86\u6709\u7528\u7684\u65b9\u6cd5\u3002<\/li>\n<li>\u5982\u679c\u60a8\u68c0\u67e5\u60a8\u7684\u81ea\u5b9a\u4e49\u5c5e\u6027\u6216\u65b9\u6cd5\u5df2\u4e0d\u5b58\u5728\u2014\u2014\u4e5f\u8bb8\u5df2\u7ecf\u5728\u4ee3\u7801\u7684\u5176\u4ed6\u5730\u65b9\u5b9e\u73b0\u6216\u5df2\u7ecf\u662f\u4f60\u652f\u6301\u7684\u6d4f\u89c8\u5668JavaScript\u5f15\u64ce\u90e8\u5206\u3002<\/li>\n<li>\u4f60\u6e05\u695a\u5730\u6587\u6863\u8bb0\u5f55\u5e76\u548c\u56e2\u961f\u4ea4\u6d41\u4e86\u53d8\u5316\u3002<\/li>\n<\/ul>\n<p>\u5982\u679c\u8fd9\u4e09\u4e2a\u6761\u4ef6\u5f97\u5230\u6ee1\u8db3\uff0c\u4f60\u53ef\u4ee5\u7ed9\u539f\u578b\u8fdb\u884c\u81ea\u5b9a\u4e49\u7684\u6dfb\u52a0\uff0c\u5f62\u5f0f\u5982\u4e0b\uff1a<\/p>\n<div class=\"zxx_code\">\n<pre>\nif (typeof Object.protoype.myMethod !== \"function\") {\n   Object.protoype.myMethod = function () {\n      <span class=\"cg\">\/\/ \u5b9e\u73b0...<\/span>\n   };\n}\n<\/pre>\n<\/div>\n<h3>switch\u5f62\u5f0f(switch Pattern )<\/h3>\n<p>\u4f60\u53ef\u4ee5\u901a\u8fc7\u7c7b\u4f3c\u4e0b\u9762\u5f62\u5f0f\u7684switch\u8bed\u53e5\u589e\u5f3a\u53ef\u8bfb\u6027\u548c\u5065\u58ee\u6027\uff1a<\/p>\n<div class=\"zxx_code\">\n<pre>\nvar inspect_me = 0,\n    result = '';\nswitch (inspect_me) {\ncase 0:\n   result = \"zero\";\n   break;\ncase 1:\n   result = \"one\";\n   break;\ndefault:\n   result = \"unknown\";\n}\n<\/pre>\n<\/div>\n<p>\u8fd9\u4e2a\u7b80\u5355\u7684\u4f8b\u5b50\u4e2d\u6240\u9075\u5faa\u7684\u98ce\u683c\u7ea6\u5b9a\u5982\u4e0b\uff1a<\/p>\n<ul id=\"ul\">\n<li>\u6bcf\u4e2acase\u548cswitch\u5bf9\u9f50\uff08\u82b1\u62ec\u53f7\u7f29\u8fdb\u89c4\u5219\u9664\u5916\uff09<\/li>\n<li>\u6bcf\u4e2acase\u4e2d\u4ee3\u7801\u7f29\u8fdb<\/li>\n<li>\u6bcf\u4e2acase\u4ee5break\u6e05\u9664\u7ed3\u675f<\/li>\n<li>\u907f\u514d\u8d2f\u7a7f\uff08\u6545\u610f\u5ffd\u7565break\uff09\u3002\u5982\u679c\u4f60\u975e\u5e38\u786e\u4fe1\u8d2f\u7a7f\u662f\u6700\u597d\u7684\u65b9\u6cd5\uff0c\u52a1\u5fc5\u8bb0\u5f55\u6b64\u60c5\u51b5\uff0c\u56e0\u4e3a\u5bf9\u4e8e\u6709\u4e9b\u9605\u8bfb\u4eba\u800c\u8a00\uff0c\u5b83\u4eec\u53ef\u80fd\u770b\u8d77\u6765\u662f\u9519\u8bef\u7684\u3002<\/li>\n<li>\u4ee5default\u7ed3\u675fswitch\uff1a\u786e\u4fdd\u603b\u6709\u5065\u5168\u7684\u7ed3\u679c\uff0c\u5373\u4f7f\u65e0\u60c5\u51b5\u5339\u914d\u3002<\/li>\n<\/ul>\n<h3>\u907f\u514d\u9690\u5f0f\u7c7b\u578b\u8f6c\u6362(Avoiding Implied Typecasting )<\/h3>\n<p>JavaScript\u7684\u53d8\u91cf\u5728\u6bd4\u8f83\u7684\u65f6\u5019\u4f1a\u9690\u5f0f\u7c7b\u578b\u8f6c\u6362\u3002\u8fd9\u5c31\u662f\u4e3a\u4ec0\u4e48\u4e00\u4e9b\u8bf8\u5982\uff1afalse == 0 \u6216 &#8220;&#8221; == 0 \u8fd4\u56de\u7684\u7ed3\u679c\u662ftrue\u3002\u4e3a\u907f\u514d\u5f15\u8d77\u6df7\u4e71\u7684\u9690\u542b\u7c7b\u578b\u8f6c\u6362\uff0c\u5728\u4f60\u6bd4\u8f83\u503c\u548c\u8868\u8fbe\u5f0f\u7c7b\u578b\u7684\u65f6\u5019\u59cb\u7ec8\u4f7f\u7528===\u548c!==\u64cd\u4f5c\u7b26\u3002<\/p>\n<div class=\"zxx_code\">\n<pre>\nvar zero = 0;\nif (zero === false) {\n   <span class=\"cg\">\/\/ \u4e0d\u6267\u884c\uff0c\u56e0\u4e3azero\u4e3a0, \u800c\u4e0d\u662ffalse<\/span>\n}\n\n<span class=\"cg\">\/\/ \u53cd\u9762\u793a\u4f8b<\/span>\nif (zero == false) {\n   <span class=\"cg\">\/\/ \u6267\u884c\u4e86...<\/span>\n}\n<\/pre>\n<\/div>\n<p>\u8fd8\u6709\u53e6\u5916\u4e00\u79cd\u601d\u60f3\u89c2\u70b9\u8ba4\u4e3a==\u5c31\u8db3\u591f\u4e86===\u662f\u591a\u4f59\u7684\u3002\u4f8b\u5982\uff0c\u5f53\u4f60\u4f7f\u7528typeof\u4f60\u5c31\u77e5\u9053\u5b83\u4f1a\u8fd4\u56de\u4e00\u4e2a\u5b57\u7b26\u4e32\uff0c\u6240\u4ee5\u6ca1\u6709\u4f7f\u7528\u4e25\u683c\u76f8\u7b49\u7684\u7406\u7531\u3002\u7136\u800c\uff0cJSLint\u8981\u6c42\u4e25\u683c\u76f8\u7b49\uff0c\u5b83\u4f7f\u4ee3\u7801\u770b\u4e0a\u53bb\u66f4\u6709\u4e00\u81f4\u6027\uff0c\u53ef\u4ee5\u964d\u4f4e\u4ee3\u7801\u9605\u8bfb\u65f6\u7684\u7cbe\u529b\u6d88\u8017\u3002\uff08\u201c==\u662f\u6545\u610f\u7684\u8fd8\u662f\u4e00\u4e2a\u758f\u6f0f\uff1f\u201d\uff09<\/p>\n<h3>\u907f\u514d(Avoiding) eval()<\/h3>\n<p>\u5982\u679c\u4f60\u73b0\u5728\u7684\u4ee3\u7801\u4e2d\u4f7f\u7528\u4e86eval()\uff0c\u8bb0\u4f4f\u8be5\u5492\u8bed\u201ceval()\u662f\u9b54\u9b3c\u201d\u3002\u6b64\u65b9\u6cd5\u63a5\u53d7\u4efb\u610f\u7684\u5b57\u7b26\u4e32\uff0c\u5e76\u5f53\u4f5cJavaScript\u4ee3\u7801\u6765\u5904\u7406\u3002\u5f53\u6709\u95ee\u9898\u7684\u4ee3\u7801\u662f\u4e8b\u5148\u77e5\u9053\u7684\uff08\u4e0d\u662f\u8fd0\u884c\u65f6\u786e\u5b9a\u7684\uff09\uff0c\u6ca1\u6709\u7406\u7531\u4f7f\u7528eval()\u3002\u5982\u679c\u4ee3\u7801\u662f\u5728\u8fd0\u884c\u65f6\u52a8\u6001\u751f\u6210\uff0c\u6709\u4e00\u4e2a\u66f4\u597d\u7684\u65b9\u5f0f\u4e0d\u4f7f\u7528eval\u800c\u8fbe\u5230\u540c\u6837\u7684\u76ee\u6807\u3002\u4f8b\u5982\uff0c\u7528\u65b9\u62ec\u53f7\u8868\u793a\u6cd5\u6765\u8bbf\u95ee\u52a8\u6001\u5c5e\u6027\u4f1a\u66f4\u597d\u66f4\u7b80\u5355\uff1a<\/p>\n<div class=\"zxx_code\">\n<pre>\n<span class=\"cg\">\/\/ \u53cd\u9762\u793a\u4f8b<\/span>\nvar property = \"name\";\nalert(eval(\"obj.\" + property));\n\n<span class=\"cg\">\/\/ \u66f4\u597d\u7684<\/span>\nvar property = \"name\";\nalert(obj[property]);\n<\/pre>\n<\/div>\n<p>\u4f7f\u7528eval()\u4e5f\u5e26\u6765\u4e86\u5b89\u5168\u9690\u60a3\uff0c\u56e0\u4e3a\u88ab\u6267\u884c\u7684\u4ee3\u7801\uff08\u4f8b\u5982\u4ece\u7f51\u7edc\u6765\uff09\u53ef\u80fd\u5df2\u88ab\u7be1\u6539\u3002\u8fd9\u662f\u4e2a\u5f88\u5e38\u89c1\u7684\u53cd\u9762\u6559\u6750\uff0c\u5f53\u5904\u7406Ajax\u8bf7\u6c42\u5f97\u5230\u7684JSON \u76f8\u5e94\u7684\u65f6\u5019\u3002\u5728\u8fd9\u4e9b\u60c5\u51b5\u4e0b\uff0c\u6700\u597d\u4f7f\u7528JavaScript\u5185\u7f6e\u65b9\u6cd5\u6765\u89e3\u6790JSON\u76f8\u5e94\uff0c\u4ee5\u786e\u4fdd\u5b89\u5168\u548c\u6709\u6548\u3002\u82e5\u6d4f\u89c8\u5668\u4e0d\u652f\u6301JSON.parse()\uff0c\u4f60\u53ef\u4ee5\u4f7f\u7528\u6765\u81eaJSON.org\u7684\u5e93\u3002<\/p>\n<p>\u540c\u6837\u91cd\u8981\u7684\u662f\u8981\u8bb0\u4f4f\uff0c\u7ed9setInterval(), setTimeout()\u548cFunction()\u6784\u9020\u51fd\u6570\u4f20\u9012\u5b57\u7b26\u4e32\uff0c\u5927\u90e8\u5206\u60c5\u51b5\u4e0b\uff0c\u4e0e\u4f7f\u7528eval()\u662f\u7c7b\u4f3c\u7684\uff0c\u56e0\u6b64\u8981\u907f\u514d\u3002\u5728\u5e55\u540e\uff0cJavaScript\u4ecd\u9700\u8981\u8bc4\u4f30\u548c\u6267\u884c\u4f60\u7ed9\u7a0b\u5e8f\u4f20\u9012\u7684\u5b57\u7b26\u4e32\uff1a<\/p>\n<div class=\"zxx_code\">\n<pre>\n<span class=\"cg\">\/\/ \u53cd\u9762\u793a\u4f8b<\/span>\nsetTimeout(\"myFunc()\", 1000);\nsetTimeout(\"myFunc(1, 2, 3)\", 1000);\n\n<span class=\"cg\">\/\/ \u66f4\u597d\u7684<\/span>\nsetTimeout(myFunc, 1000);\nsetTimeout(function () {\n   myFunc(1, 2, 3);\n}, 1000);\n<\/pre>\n<\/div>\n<p>\u4f7f\u7528\u65b0\u7684Function()\u6784\u9020\u5c31\u7c7b\u4f3c\u4e8eeval()\uff0c\u5e94\u5c0f\u5fc3\u63a5\u8fd1\u3002\u8fd9\u53ef\u80fd\u662f\u4e00\u4e2a\u5f3a\u5927\u7684\u6784\u9020\uff0c\u4f46\u5f80\u5f80\u88ab\u8bef\u7528\u3002\u5982\u679c\u4f60\u7edd\u5bf9\u5fc5\u987b\u4f7f\u7528eval()\uff0c\u4f60\u53ef\u4ee5\u8003\u8651\u4f7f\u7528new Function()\u4ee3\u66ff\u3002\u6709\u4e00\u4e2a\u5c0f\u7684\u6f5c\u5728\u597d\u5904\uff0c\u56e0\u4e3a\u5728\u65b0Function()\u4e2d\u4f5c\u4ee3\u7801\u8bc4\u4f30\u662f\u5728\u5c40\u90e8\u51fd\u6570\u4f5c\u7528\u57df\u4e2d\u8fd0\u884c\uff0c\u6240\u4ee5\u4ee3\u7801\u4e2d\u4efb\u4f55\u88ab\u8bc4\u4f30\u7684\u901a\u8fc7var\u5b9a\u4e49\u7684\u53d8\u91cf\u90fd\u4e0d\u4f1a\u81ea\u52a8\u53d8\u6210\u5168\u5c40\u53d8\u91cf\u3002\u53e6\u4e00\u79cd\u65b9\u6cd5\u6765\u963b\u6b62\u81ea\u52a8\u5168\u5c40\u53d8\u91cf\u662f\u5c01\u88c5eval()\u8c03\u7528\u5230\u4e00\u4e2a\u5373\u65f6\u51fd\u6570\u4e2d\u3002<\/p>\n<p>\u8003\u8651\u4e0b\u9762\u8fd9\u4e2a\u4f8b\u5b50\uff0c\u8fd9\u91cc\u4ec5<code>un<\/code>\u4f5c\u4e3a\u5168\u5c40\u53d8\u91cf\u6c61\u67d3\u4e86\u547d\u540d\u7a7a\u95f4\u3002<\/p>\n<div class=\"zxx_code\">\n<pre>\nconsole.log(typeof un);\t<span class=\"cg\">\/\/ \"undefined\"<\/span>\nconsole.log(typeof deux); <span class=\"cg\">\/\/ \"undefined\"<\/span>\nconsole.log(typeof trois); <span class=\"cg\">\/\/ \"undefined\"<\/span>\n\nvar jsstring = \"var un = 1; console.log(un);\";\neval(jsstring); <span class=\"cg\">\/\/ logs \"1\"<\/span>\n\njsstring = \"var deux = 2; console.log(deux);\";\nnew Function(jsstring)(); <span class=\"cg\">\/\/ logs \"2\"<\/span>\n\njsstring = \"var trois = 3; console.log(trois);\";\n(function () {\n   eval(jsstring);\n}()); <span class=\"cg\">\/\/ logs \"3\"<\/span>\n\nconsole.log(typeof un); <span class=\"cg\">\/\/ number<\/span>\nconsole.log(typeof deux); <span class=\"cg\">\/\/ \"undefined\"<\/span>\nconsole.log(typeof trois); <span class=\"cg\">\/\/ \"undefined\"<\/span>\n<\/pre>\n<\/div>\n<p>\u53e6\u4e00\u95f4eval()\u548cFunction\u6784\u9020\u4e0d\u540c\u7684\u662feval()\u53ef\u4ee5\u5e72\u6270\u4f5c\u7528\u57df\u94fe\uff0c\u800cFunction()\u66f4\u5b89\u5206\u5b88\u5df1\u4e9b\u3002\u4e0d\u7ba1\u4f60\u5728\u54ea\u91cc\u6267\u884cFunction()\uff0c\u5b83\u53ea\u770b\u5230\u5168\u5c40\u4f5c\u7528\u57df\u3002\u6240\u4ee5\u5176\u80fd\u5f88\u597d\u7684\u907f\u514d\u672c\u5730\u53d8\u91cf\u6c61\u67d3\u3002\u5728\u4e0b\u9762\u8fd9\u4e2a\u4f8b\u5b50\u4e2d\uff0ceval()\u53ef\u4ee5\u8bbf\u95ee\u548c\u4fee\u6539\u5b83\u5916\u90e8\u4f5c\u7528\u57df\u4e2d\u7684\u53d8\u91cf\uff0c\u8fd9\u662fFunction\u505a\u4e0d\u6765\u7684\uff08\u6ce8\u610f\u5230\u4f7f\u7528Function\u548cnew Function\u662f\u76f8\u540c\u7684\uff09\u3002<\/p>\n<div class=\"zxx_code\">\n<pre>\n(function () {\n   var local = 1;\n   eval(\"local = 3; console.log(local)\"); <span class=\"cg\">\/\/ logs \"3\"<\/span>\n   console.log(local); <span class=\"cg\">\/\/ logs \"3\"<\/span>\n}());\n\n(function () {\n   var local = 1;\n   Function(\"console.log(typeof local);\")(); <span class=\"cg\">\/\/ logs undefined<\/span>\n}());\n<\/pre>\n<\/div>\n<h3>parseInt()\u4e0b\u7684\u6570\u503c\u8f6c\u6362(Number Conversions with parseInt())<\/h3>\n<p>\u4f7f\u7528parseInt()\u4f60\u53ef\u4ee5\u4ece\u5b57\u7b26\u4e32\u4e2d\u83b7\u53d6\u6570\u503c\uff0c\u8be5\u65b9\u6cd5\u63a5\u53d7\u53e6\u4e00\u4e2a\u57fa\u6570\u53c2\u6570\uff0c\u8fd9\u7ecf\u5e38\u7701\u7565\uff0c\u4f46\u4e0d\u5e94\u8be5\u3002\u5f53\u5b57\u7b26\u4e32\u4ee5&#8221;0&#8243;\u5f00\u5934\u7684\u65f6\u5019\u5c31\u6709\u53ef\u80fd\u4f1a\u51fa\u95ee\u9898\uff0c\u4f8b\u5982\uff0c\u90e8\u5206\u65f6\u95f4\u8fdb\u5165\u8868\u5355\u57df\uff0c\u5728ECMAScript 3\u4e2d\uff0c\u5f00\u5934\u4e3a&#8221;0&#8243;\u7684\u5b57\u7b26\u4e32\u88ab\u5f53\u505a8\u8fdb\u5236\u5904\u7406\u4e86\uff0c\u4f46\u8fd9\u5df2\u5728ECMAScript 5\u4e2d\u6539\u53d8\u4e86\u3002\u4e3a\u4e86\u907f\u514d\u77db\u76fe\u548c\u610f\u5916\u7684\u7ed3\u679c\uff0c\u603b\u662f\u6307\u5b9a\u57fa\u6570\u53c2\u6570\u3002<\/p>\n<div class=\"zxx_code\">\n<pre>var month = \"06\",\n    year = \"09\";\nmonth = parseInt(month, 10);\nyear = parseInt(year, 10);<\/pre>\n<\/div>\n<p>\u6b64\u4f8b\u4e2d\uff0c\u5982\u679c\u4f60\u5ffd\u7565\u4e86\u57fa\u6570\u53c2\u6570\uff0c\u5982parseInt(year)\uff0c\u8fd4\u56de\u7684\u503c\u5c06\u662f0\uff0c\u56e0\u4e3a\u201c09\u201d\u88ab\u5f53\u505a8\u8fdb\u5236\uff08\u597d\u6bd4\u6267\u884c parseInt( year, 8 )\uff09\uff0c\u800c09\u57288\u8fdb\u5236\u4e2d\u4e0d\u662f\u4e2a\u6709\u6548\u6570\u5b57\u3002<\/p>\n<p>\u66ff\u6362\u65b9\u6cd5\u662f\u5c06\u5b57\u7b26\u4e32\u8f6c\u6362\u6210\u6570\u5b57\uff0c\u5305\u62ec\uff1a<\/p>\n<div class=\"zxx_code\">\n<pre>\n+\"08\" <span class=\"cg\">\/\/ \u7ed3\u679c\u662f 8<\/span>\nNumber(\"08\") <span class=\"cg\">\/\/ 8<\/span>\n<\/pre>\n<\/div>\n<p>\u8fd9\u4e9b\u901a\u5e38\u5feb\u4e8eparseInt()\uff0c\u56e0\u4e3aparseInt()\u65b9\u6cd5\uff0c\u987e\u540d\u601d\u610f\uff0c\u4e0d\u662f\u7b80\u5355\u5730\u89e3\u6790\u4e0e\u8f6c\u6362\u3002\u4f46\u662f\uff0c\u5982\u679c\u4f60\u60f3\u8f93\u5165\u4f8b\u5982\u201c08 hello\u201d\uff0cparseInt()\u5c06\u8fd4\u56de\u6570\u5b57\uff0c\u800c\u5176\u5b83\u4ee5NaN\u544a\u7ec8\u3002<\/p>\n<h3>\u7f16\u7801\u89c4\u8303(Coding Conventions)<\/h3>\n<p>\u5efa\u7acb\u548c\u9075\u5faa\u7f16\u7801\u89c4\u8303\u662f\u5f88\u91cd\u8981\u7684\uff0c\u8fd9\u8ba9\u4f60\u7684\u4ee3\u7801\u4fdd\u6301\u4e00\u81f4\u6027\uff0c\u53ef\u9884\u6d4b\uff0c\u66f4\u6613\u4e8e\u9605\u8bfb\u548c\u7406\u89e3\u3002\u4e00\u4e2a\u65b0\u7684\u5f00\u53d1\u8005\u52a0\u5165\u8fd9\u4e2a\u56e2\u961f\u53ef\u4ee5\u901a\u8bfb\u89c4\u8303\uff0c\u7406\u89e3\u5176\u5b83\u56e2\u961f\u6210\u5458\u4e66\u5199\u7684\u4ee3\u7801\uff0c\u66f4\u5feb\u4e0a\u624b\u5e72\u6d3b\u3002<\/p>\n<p>\u8bb8\u591a\u6fc0\u70c8\u7684\u4e89\u8bba\u53d1\u751f\u4f1a\u8bae\u4e0a\u6216\u662f\u90ae\u4ef6\u5217\u8868\u4e0a\uff0c\u95ee\u9898\u5f80\u5f80\u9488\u5bf9\u67d0\u4e9b\u4ee3\u7801\u89c4\u8303\u7684\u7279\u5b9a\u65b9\u9762\uff08\u4f8b\u5982\u4ee3\u7801\u7f29\u8fdb\uff0c\u662fTab\u5236\u8868\u7b26\u952e\u8fd8\u662fspace\u7a7a\u683c\u952e\uff09\u3002\u5982\u679c\u4f60\u662f\u4f60\u7ec4\u7ec7\u4e2d\u5efa\u8bae\u91c7\u7528\u89c4\u8303\u7684\uff0c\u51c6\u5907\u597d\u9762\u5bf9\u5404\u79cd\u53cd\u5bf9\u7684\u6216\u662f\u542c\u8d77\u6765\u4e0d\u540c\u4f46\u5f88\u5f3a\u70c8\u7684\u89c2\u70b9\u3002\u8981\u8bb0\u4f4f\uff0c\u5efa\u7acb\u548c\u575a\u5b9a\u4e0d\u79fb\u5730\u9075\u5faa\u89c4\u8303\u8981\u6bd4\u7ea0\u7ed3\u4e8e\u89c4\u8303\u7684\u7ec6\u8282\u91cd\u8981\u7684\u591a\u3002<\/p>\n<h3>\u7f29\u8fdb(Indentation)<\/h3>\n<p>\u4ee3\u7801\u6ca1\u6709\u7f29\u8fdb\u57fa\u672c\u4e0a\u5c31\u4e0d\u80fd\u8bfb\u4e86\u3002\u552f\u4e00\u7cdf\u7cd5\u7684\u4e8b\u60c5\u5c31\u662f\u4e0d\u4e00\u81f4\u7684\u7f29\u8fdb\uff0c\u56e0\u4e3a\u5b83\u770b\u4e0a\u53bb\u50cf\u662f\u9075\u5faa\u4e86\u89c4\u8303\uff0c\u4f46\u662f\u53ef\u80fd\u4e00\u8def\u4e0a\u4f34\u968f\u7740\u6df7\u4e71\u548c\u60ca\u5947\u3002\u91cd\u8981\u7684\u662f\u89c4\u8303\u5730\u4f7f\u7528\u7f29\u8fdb\u3002<\/p>\n<p>\u4e00\u4e9b\u5f00\u53d1\u4eba\u5458\u66f4\u559c\u6b22\u7528tab\u5236\u8868\u7b26\u7f29\u8fdb\uff0c\u56e0\u4e3a\u4efb\u4f55\u4eba\u90fd\u53ef\u4ee5\u8c03\u6574\u4ed6\u4eec\u7684\u7f16\u8f91\u5668\u4ee5\u81ea\u5df1\u559c\u6b22\u7684\u7a7a\u683c\u6570\u6765\u663e\u793aTab\u3002\u6709\u4e9b\u4eba\u559c\u6b22\u7a7a\u683c\u2014\u2014\u901a\u5e38\u56db\u4e2a\uff0c\u8fd9\u90fd\u65e0\u6240\u8c13\uff0c\u53ea\u8981\u56e2\u961f\u6bcf\u4e2a\u4eba\u90fd\u9075\u5faa\u540c\u4e00\u4e2a\u89c4\u8303\u5c31\u597d\u4e86\u3002\u8fd9\u672c\u4e66\uff0c\u4f8b\u5982\uff0c\u4f7f\u7528\u56db\u4e2a\u7a7a\u683c\u7f29\u8fdb\uff0c\u8fd9\u4e5f\u662fJSLint\u4e2d\u9ed8\u8ba4\u7684\u7f29\u8fdb\u3002<\/p>\n<p>\u4ec0\u4e48\u5e94\u8be5\u7f29\u8fdb\u5462\uff1f\u89c4\u5219\u5f88\u7b80\u5355\u2014\u2014\u82b1\u62ec\u53f7\u91cc\u9762\u7684\u4e1c\u897f\u3002\u8fd9\u5c31\u610f\u5473\u7740\u51fd\u6570\u4f53\uff0c\u5faa\u73af (do, while, for, for-in)\uff0cif\uff0cswitch\uff0c\u4ee5\u53ca\u5bf9\u8c61\u5b57\u9762\u91cf\u4e2d\u7684\u5bf9\u8c61\u5c5e\u6027\u3002\u4e0b\u9762\u7684\u4ee3\u7801\u5c31\u662f\u4f7f\u7528\u7f29\u8fdb\u7684\u793a\u4f8b\uff1a<\/p>\n<div class=\"zxx_code\">\n<pre>function outer(a, b) {\n    var c = 1,\n        d = 2,\n        inner;\n    if (a > b) {\n        inner = function () {\n            return {\n                r: c - d\n            };\n        };\n    } else {\n        inner = function () {\n            return {\n                r: c + d\n            };\n        };\n    }\n    return inner;\n}<\/pre>\n<\/div>\n<h3>\u82b1\u62ec\u53f7{}(Curly Braces)<\/h3>\n<p>\u82b1\u62ec\u53f7\uff08\u4ea6\u79f0\u5927\u62ec\u53f7\uff0c\u4e0b\u540c\uff09\u5e94\u603b\u88ab\u4f7f\u7528\uff0c\u5373\u4f7f\u5728\u5b83\u4eec\u4e3a\u53ef\u9009\u7684\u65f6\u5019\u3002\u6280\u672f\u4e0a\u5c06\uff0c\u5728in\u6216\u662ffor\u4e2d\u5982\u679c\u8bed\u53e5\u4ec5\u4e00\u6761\uff0c\u82b1\u62ec\u53f7\u662f\u4e0d\u9700\u8981\u7684\uff0c\u4f46\u662f\u4f60\u8fd8\u662f\u5e94\u8be5\u603b\u662f\u4f7f\u7528\u5b83\u4eec\uff0c\u8fd9\u4f1a\u8ba9\u4ee3\u7801\u66f4\u6709\u6301\u7eed\u6027\u548c\u6613\u4e8e\u66f4\u65b0\u3002<\/p>\n<p>\u60f3\u8c61\u4e0b\u4f60\u6709\u4e00\u4e2a\u53ea\u6709\u4e00\u6761\u8bed\u53e5\u7684for\u5faa\u73af\uff0c\u4f60\u53ef\u4ee5\u5ffd\u7565\u82b1\u62ec\u53f7\uff0c\u800c\u6ca1\u6709\u89e3\u6790\u7684\u9519\u8bef\u3002<\/p>\n<div class=\"zxx_code\">\n<pre><span class=\"cg\">\/\/ \u7cdf\u7cd5\u7684\u5b9e\u4f8b<\/span>\nfor (var i = 0; i < 10; i += 1)\n   alert(i);<\/pre>\n<\/div>\n<p>\u4f46\u662f\uff0c\u5982\u679c\uff0c\u540e\u6765\uff0c\u4e3b\u4f53\u5faa\u73af\u90e8\u5206\u53c8\u589e\u52a0\u4e86\u884c\u4ee3\u7801\uff1f<\/p>\n<div class=\"zxx_code\">\n<pre>\n<span class=\"cg\">\/\/ \u7cdf\u7cd5\u7684\u5b9e\u4f8b<\/span>\nfor (var i = 0; i < 10; i += 1)\n   alert(i);\n   alert(i + \" is \" + (i % 2 ? \"odd\" : \"even\"));\n<\/pre>\n<\/div>\n<p>\u7b2c\u4e8c\u4e2aalert\u5df2\u7ecf\u5728\u5faa\u73af\u4e4b\u5916\uff0c\u7f29\u8fdb\u53ef\u80fd\u6b3a\u9a97\u4e86\u4f60\u3002\u4e3a\u4e86\u957f\u8fdc\u6253\u7b97\uff0c\u6700\u597d\u603b\u662f\u4f7f\u7528\u82b1\u62ec\u53f7\uff0c\u5373\u65f6\u503c\u4e00\u884c\u4ee3\u7801\uff1a<\/p>\n<div class=\"zxx_code\">\n<pre>\n<span class=\"cg\">\/\/ \u597d\u7684\u5b9e\u4f8b<\/span>\nfor (var i = 0; i < 10; i += 1) {\n   alert(i);\n}\n<\/pre>\n<\/div>\n<p>if\u6761\u4ef6\u7c7b\u4f3c\uff1a<\/p>\n<div class=\"zxx_code\">\n<pre>\n<span class=\"cg\">\/\/ \u574f<\/span>\nif (true)\n   alert(1);\nelse\n   alert(2);\n\n<span class=\"cg\">\/\/ \u597d<\/span>\nif (true) {\n   alert(1);\n} else {\n   alert(2);\n}\n<\/pre>\n<\/div>\n<h3>\u5de6\u82b1\u62ec\u53f7\u7684\u4f4d\u7f6e(Opening Brace Location)<\/h3>\n<p>\u5f00\u53d1\u4eba\u5458\u5bf9\u4e8e\u5de6\u5927\u62ec\u53f7\u7684\u4f4d\u7f6e\u6709\u7740\u4e0d\u540c\u7684\u504f\u597d\u2014\u2014\u5728\u540c\u4e00\u884c\u6216\u662f\u4e0b\u4e00\u884c\u3002<\/p>\n<div class=\"zxx_code\">\n<pre>if (true) {\n   alert(\"It's TRUE!\");\n}<\/pre>\n<\/div>\n<p>\u6216<\/p>\n<div class=\"zxx_code\">\n<pre>if (true) \n{\n   alert(\"It's TRUE!\");\n}<\/pre>\n<\/div>\n<p>\u8fd9\u4e2a\u5b9e\u4f8b\u4e2d\uff0c\u4ec1\u8005\u89c1\u4ec1\u667a\u8005\u89c1\u667a\uff0c\u4f46\u4e5f\u6709\u4e2a\u6848\uff0c\u62ec\u53f7\u4f4d\u7f6e\u4e0d\u540c\u4f1a\u6709\u4e0d\u540c\u7684\u884c\u4e3a\u8868\u73b0\u3002\u8fd9\u662f\u56e0\u4e3a\u5206\u53f7\u63d2\u5165\u673a\u5236(semicolon insertion mechanism)\u2014\u2014JavaScript\u662f\u4e0d\u6311\u5254\u7684\uff0c\u5f53\u4f60\u9009\u62e9\u4e0d\u4f7f\u7528\u5206\u53f7\u7ed3\u675f\u4e00\u884c\u4ee3\u7801\u65f6JavaScript\u4f1a\u81ea\u5df1\u5e2e\u4f60\u8865\u4e0a\u3002\u8fd9\u79cd\u884c\u4e3a\u53ef\u80fd\u4f1a\u5bfc\u81f4\u9ebb\u70e6\uff0c\u5982\u5f53\u4f60\u8fd4\u56de\u5bf9\u8c61\u5b57\u9762\u91cf\uff0c\u800c\u5de6\u62ec\u53f7\u5374\u5728\u4e0b\u4e00\u884c\u7684\u65f6\u5019\uff1a<\/p>\n<div class=\"zxx_code\">\n<pre><span class=\"cg\">\/\/ \u8b66\u544a\uff1a \u610f\u5916\u7684\u8fd4\u56de\u503c<\/span>\nfunction func() {\n   return\n  <span class=\"cg\">\/\/ \u4e0b\u9762\u4ee3\u7801\u4e0d\u6267\u884c<\/span>\n   {\n      name : \"Batman\"\n   }\n}<\/pre>\n<\/div>\n<p>\u5982\u679c\u4f60\u5e0c\u671b\u51fd\u6570\u8fd4\u56de\u4e00\u4e2a\u542b\u6709name\u5c5e\u6027\u7684\u5bf9\u8c61\uff0c\u4f60\u4f1a\u60ca\u8bb6\u3002\u7531\u4e8e\u9690\u542b\u5206\u53f7\uff0c\u51fd\u6570\u8fd4\u56deundefined\u3002\u524d\u9762\u7684\u4ee3\u7801\u7b49\u4ef7\u4e8e\uff1a<\/p>\n<div class=\"zxx_code\">\n<pre><span class=\"cg\">\/\/ \u8b66\u544a\uff1a \u610f\u5916\u7684\u8fd4\u56de\u503c<\/span>\nfunction func() {\n   return undefined; \n  <span class=\"cg\">\/\/ \u4e0b\u9762\u4ee3\u7801\u4e0d\u6267\u884c<\/span>\n   {\n      name : \"Batman\"\n   }\n}<\/pre>\n<\/div>\n<p>\u603b\u4e4b\uff0c\u603b\u662f\u4f7f\u7528\u82b1\u62ec\u53f7\uff0c\u5e76\u59cb\u7ec8\u628a\u5728\u4e0e\u4e4b\u524d\u7684\u8bed\u53e5\u653e\u5728\u540c\u4e00\u884c\uff1a<\/p>\n<div class=\"zxx_code\">\n<pre>\nfunction func() {\n   return {\n      name : \"Batman\"\n   };\n}\n<\/pre>\n<\/div>\n<blockquote><p>\n\u5173\u4e8e\u5206\u53f7\u6ce8\uff1a\u5c31\u50cf\u4f7f\u7528\u82b1\u62ec\u53f7\uff0c\u4f60\u5e94\u8be5\u603b\u662f\u4f7f\u7528\u5206\u53f7\uff0c\u5373\u4f7f\u4ed6\u4eec\u53ef\u7531JavaScript\u89e3\u6790\u5668\u9690\u5f0f\u521b\u5efa\u3002\u8fd9\u4e0d\u4ec5\u4fc3\u8fdb\u66f4\u79d1\u5b66\u548c\u66f4\u4e25\u683c\u7684\u4ee3\u7801\uff0c\u800c\u4e14\u6709\u52a9\u4e8e\u89e3\u51b3\u5b58\u6709\u7591\u60d1\u7684\u5730\u65b9\uff0c\u5c31\u5982\u524d\u9762\u7684\u4f8b\u5b50\u663e\u793a\u3002\n<\/p><\/blockquote>\n<h3>\u7a7a\u683c(White Space)<\/h3>\n<p>\u7a7a\u683c\u7684\u4f7f\u7528\u540c\u6837\u6709\u52a9\u4e8e\u6539\u5584\u4ee3\u7801\u7684\u53ef\u8bfb\u6027\u548c\u4e00\u81f4\u6027\u3002\u5728\u5199\u82f1\u6587\u53e5\u5b50\u7684\u65f6\u5019\uff0c\u5728\u9017\u53f7\u548c\u53e5\u53f7\u540e\u9762\u4f1a\u4f7f\u7528\u95f4\u9694\u3002\u5728JavaScript\u4e2d\uff0c\u4f60\u53ef\u4ee5\u6309\u7167\u540c\u6837\u7684\u903b\u8f91\u5728\u5217\u8868\u6a21\u6837\u8868\u8fbe\u5f0f\uff08\u76f8\u5f53\u4e8e\u9017\u53f7\uff09\u548c\u7ed3\u675f\u8bed\u53e5\uff08\u76f8\u5bf9\u4e8e\u5b8c\u6210\u4e86\u201c\u60f3\u6cd5\u201d\uff09\u540e\u9762\u6dfb\u52a0\u95f4\u9694\u3002<\/p>\n<p>\u9002\u5408\u4f7f\u7528\u7a7a\u683c\u7684\u5730\u65b9\u5305\u62ec\uff1a<\/p>\n<ul id=\"ul\">\n<li>for\u5faa\u73af\u5206\u53f7\u5206\u5f00\u540e\u7684\u7684\u90e8\u5206\uff1a\u5982<code>for (var i = 0; i < 10; i += 1) {...}<\/code><\/li>\n<li>for\u5faa\u73af\u4e2d\u521d\u59cb\u5316\u7684\u591a\u53d8\u91cf(i\u548cmax)\uff1a<code>for (var i = 0, max = 10; i < max; i += 1) {...}<\/code><\/li>\n<li>\u5206\u9694\u6570\u7ec4\u9879\u7684\u9017\u53f7\u7684\u540e\u9762\uff1a<code>var a = [1, 2, 3];<\/code><\/li>\n<li>\u5bf9\u8c61\u5c5e\u6027\u9017\u53f7\u7684\u540e\u9762\u4ee5\u53ca\u5206\u9694\u5c5e\u6027\u540d\u548c\u5c5e\u6027\u503c\u7684\u5192\u53f7\u7684\u540e\u9762\uff1a<code>var o = {a: 1, b: 2};<\/code><\/li>\n<li>\u9650\u5b9a\u51fd\u6570\u53c2\u6570\uff1a<code>myFunc(a, b, c)<\/code><\/li>\n<li>\u51fd\u6570\u58f0\u660e\u7684\u82b1\u62ec\u53f7\u7684\u524d\u9762\uff1a<code>function myFunc() {}<\/code><\/li>\n<li>\u533f\u540d\u51fd\u6570\u8868\u8fbe\u5f0ffunction\u7684\u540e\u9762\uff1a<code>var myFunc = function () {};<\/code><\/li>\n<\/ul>\n<p>\u4f7f\u7528\u7a7a\u683c\u5206\u5f00\u6240\u6709\u7684\u64cd\u4f5c\u7b26\u548c\u64cd\u4f5c\u5bf9\u8c61\u662f\u53e6\u4e00\u4e2a\u4e0d\u9519\u7684\u4f7f\u7528\uff0c\u8fd9\u610f\u5473\u7740\u5728<code>+, -, *, =, <, >, <=, >=, ===, !==, &&, ||, +=<\/code>\u7b49\u524d\u540e\u90fd\u9700\u8981\u7a7a\u683c\u3002<\/p>\n<div class=\"zxx_code\">\n<pre>\n<span class=\"cg\">\/\/ \u5bbd\u677e\u4e00\u81f4\u7684\u95f4\u8ddd\n\/\/ \u4f7f\u4ee3\u7801\u66f4\u6613\u8bfb\n\/\/ \u4f7f\u5f97\u66f4\u52a0\u201c\u900f\u6c14\u201d<\/span>\nvar d = 0,\n    a = b + 1;\nif (a && b && c) {\n    d = a % c;\n    a += d;\n}\n\n<span class=\"cg\">\/\/ \u53cd\u9762\u4f8b\u5b50\n\/\/ \u7f3a\u5931\u6216\u95f4\u8ddd\u4e0d\u4e00\n\/\/ \u4f7f\u4ee3\u7801\u53d8\u5f97\u7591\u60d1<\/span>\nvar d = 0,\n    a = b + 1;\nif (a && b && c) {\n    d = a % c;\n    a += d;\n}\n<\/pre>\n<\/div>\n<p><span class=\"s\">\/\/zxx:\u6211\u5c31\u7422\u78e8\u7740\u8fd9\u6b63\u9762\u548c\u53cd\u9762\u4f8b\u5b50\u4e0d\u957f\u5f97\u4e00\u6837\u5417...\u539f\u6587\u5c31\u662f\u5982\u6b64\uff0c\u6211\u4e5f\u4e0d\u597d\u64c5\u81ea\u6539\u52a8\u3002<\/span><\/p>\n<p>\u6700\u540e\u9700\u8981\u6ce8\u610f\u7684\u4e00\u4e2a\u7a7a\u683c\u2014\u2014\u82b1\u62ec\u53f7\u95f4\u8ddd\u3002\u6700\u597d\u4f7f\u7528\u7a7a\u683c\uff1a<\/p>\n<ul id=\"ul\">\n<li>\u51fd\u6570\u3001if-else\u8bed\u53e5\u3001\u5faa\u73af\u3001\u5bf9\u8c61\u5b57\u9762\u91cf\u7684\u5de6\u82b1\u62ec\u53f7\u7684\u524d\u9762({)<\/li>\n<li>else\u6216while\u4e4b\u95f4\u7684\u53f3\u82b1\u62ec\u53f7(})<\/li>\n<\/ul>\n<p>\u7a7a\u683c\u4f7f\u7528\u7684\u4e00\u70b9\u4e0d\u8db3\u5c31\u662f\u589e\u52a0\u4e86\u6587\u4ef6\u7684\u5927\u5c0f\uff0c\u4f46\u662f\u538b\u7f29\u65e0\u6b64\u95ee\u9898\u3002<\/p>\n<blockquote><p>\u6709\u4e00\u4e2a\u7ecf\u5e38\u88ab\u5ffd\u7565\u7684\u4ee3\u7801\u53ef\u8bfb\u6027\u65b9\u9762\u662f\u5782\u76f4\u7a7a\u683c\u7684\u4f7f\u7528\u3002\u4f60\u53ef\u4ee5\u4f7f\u7528\u7a7a\u884c\u6765\u5206\u9694\u4ee3\u7801\u5355\u5143\uff0c\u5c31\u50cf\u662f\u6587\u5b66\u4f5c\u54c1\u4e2d\u4f7f\u7528\u6bb5\u843d\u5206\u9694\u4e00\u6837\u3002<\/p><\/blockquote>\n<h3>\u547d\u540d\u89c4\u8303(Naming Conventions)<\/h3>\n<p>\u53e6\u4e00\u79cd\u65b9\u6cd5\u8ba9\u4f60\u7684\u4ee3\u7801\u66f4\u5177\u53ef\u9884\u6d4b\u6027\u548c\u53ef\u7ef4\u62a4\u6027\u662f\u91c7\u7528\u547d\u540d\u89c4\u8303\u3002\u8fd9\u5c31\u610f\u5473\u7740\u4f60\u9700\u8981\u7528\u540c\u4e00\u79cd\u5f62\u5f0f\u7ed9\u4f60\u7684\u53d8\u91cf\u548c\u51fd\u6570\u547d\u540d\u3002<\/p>\n<p>\u4e0b\u9762\u662f\u5efa\u8bae\u7684\u4e00\u4e9b\u547d\u540d\u89c4\u8303\uff0c\u4f60\u53ef\u4ee5\u539f\u6837\u91c7\u7528\uff0c\u4e5f\u53ef\u4ee5\u6839\u636e\u81ea\u5df1\u7684\u559c\u597d\u4f5c\u8c03\u6574\u3002\u540c\u6837\uff0c\u9075\u5faa\u89c4\u8303\u8981\u6bd4\u89c4\u8303\u662f\u4ec0\u4e48\u66f4\u91cd\u8981\u3002<\/p>\n<h3>\u4ee5\u5927\u5199\u5b57\u6bcd\u5199\u6784\u9020\u51fd\u6570(Capitalizing Constructors)<\/h3>\n<p>JavaScript\u5e76\u6ca1\u6709\u7c7b\uff0c\u4f46\u6709new\u8c03\u7528\u7684\u6784\u9020\u51fd\u6570\uff1a<\/p>\n<div class=\"zxx_code\">\n<pre>var adam = new Person();  <\/pre>\n<\/div>\n<p>\u56e0\u4e3a\u6784\u9020\u51fd\u6570\u4ecd\u4ec5\u4ec5\u662f\u51fd\u6570\uff0c\u4ec5\u770b\u51fd\u6570\u540d\u5c31\u53ef\u4ee5\u5e2e\u52a9\u544a\u8bc9\u4f60\u8fd9\u5e94\u8be5\u662f\u4e00\u4e2a\u6784\u9020\u51fd\u6570\u8fd8\u662f\u4e00\u4e2a\u6b63\u5e38\u7684\u51fd\u6570\u3002<\/p>\n<p>\u547d\u540d\u6784\u9020\u51fd\u6570\u65f6\u9996\u5b57\u6bcd\u5927\u5199\u5177\u6709\u6697\u793a\u4f5c\u7528\uff0c\u4f7f\u7528\u5c0f\u5199\u547d\u540d\u7684\u51fd\u6570\u548c\u65b9\u6cd5\u4e0d\u5e94\u8be5\u4f7f\u7528new\u8c03\u7528\uff1a<\/p>\n<div class=\"zxx_code\">\n<pre>\nfunction MyConstructor() {...}\nfunction myFunction() {...}\n<\/pre>\n<\/div>\n<h3>\u5206\u9694\u5355\u8bcd(Separating Words)<\/h3>\n<p>\u5f53\u4f60\u7684\u53d8\u91cf\u6216\u662f\u51fd\u6570\u540d\u6709\u591a\u4e2a\u5355\u8bcd\u7684\u65f6\u5019\uff0c\u6700\u597d\u5355\u8bcd\u7684\u5206\u79bb\u9075\u5faa\u7edf\u4e00\u7684\u89c4\u8303\uff0c\u6709\u4e00\u4e2a\u5e38\u89c1\u7684\u505a\u6cd5\u88ab\u79f0\u4f5c\u201c\u9a7c\u5cf0(Camel)\u547d\u540d\u6cd5\u201d\uff0c\u5c31\u662f\u5355\u8bcd\u5c0f\u5199\uff0c\u6bcf\u4e2a\u5355\u8bcd\u7684\u9996\u5b57\u6bcd\u5927\u5199\u3002<\/p>\n<p>\u5bf9\u4e8e\u6784\u9020\u51fd\u6570\uff0c\u53ef\u4ee5\u4f7f\u7528\u5927\u9a7c\u5cf0\u5f0f\u547d\u540d\u6cd5(upper camel case)\uff0c\u5982<code>MyConstructor()<\/code>\u3002\u5bf9\u4e8e\u51fd\u6570\u548c\u65b9\u6cd5\u540d\u79f0\uff0c\u4f60\u53ef\u4ee5\u4f7f\u7528\u5c0f\u9a7c\u5cf0\u5f0f\u547d\u540d\u6cd5(lower camel case)\uff0c\u50cf\u662f<code>myFunction(), calculateArea()<\/code>\u548c<code>getFirstName()<\/code>\u3002<\/p>\n<p>\u8981\u662f\u53d8\u91cf\u4e0d\u662f\u51fd\u6570\u5462\uff1f\u5f00\u53d1\u8005\u901a\u5e38\u4f7f\u7528\u5c0f\u9a7c\u5cf0\u5f0f\u547d\u540d\u6cd5\uff0c\u4f46\u8fd8\u6709\u53e6\u5916\u4e00\u79cd\u505a\u6cd5\u5c31\u662f\u6240\u6709\u5355\u8bcd\u5c0f\u5199\u4ee5\u4e0b\u5212\u7ebf\u8fde\u63a5\uff1a\u4f8b\u5982\uff0c<code>first_name, favorite_bands, <\/code>\u548c<code> old_company_name<\/code>\uff0c\u8fd9\u79cd\u6807\u8bb0\u6cd5\u5e2e\u4f60\u76f4\u89c2\u5730\u533a\u5206\u51fd\u6570\u548c\u5176\u4ed6\u6807\u8bc6\u2014\u2014\u539f\u578b\u548c\u5bf9\u8c61\u3002<\/p>\n<p>ECMAScript\u7684\u5c5e\u6027\u548c\u65b9\u6cd5\u5747\u4f7f\u7528Camel\u6807\u8bb0\u6cd5\uff0c\u5c3d\u7ba1\u591a\u5b57\u7684\u5c5e\u6027\u540d\u79f0\u662f\u7f55\u89c1\u7684\uff08\u6b63\u5219\u8868\u8fbe\u5f0f\u5bf9\u8c61\u7684lastIndex\u548cignoreCase\u5c5e\u6027\uff09\u3002<\/p>\n<h3>\u5176\u5b83\u547d\u540d\u5f62\u5f0f(Other Naming Patterns)<\/h3>\n<p>\u6709\u65f6\uff0c\u5f00\u53d1\u4eba\u5458\u4f7f\u7528\u547d\u540d\u89c4\u8303\u6765\u5f25\u8865\u6216\u66ff\u4ee3\u8bed\u8a00\u7279\u6027\u3002<\/p>\n<p>\u4f8b\u5982\uff0cJavaScript\u4e2d\u6ca1\u6709\u5b9a\u4e49\u5e38\u91cf\u7684\u65b9\u6cd5\uff08\u5c3d\u7ba1\u6709\u4e9b\u5185\u7f6e\u7684\u50cfNumber, MAX_VALUE\uff09\uff0c\u6240\u4ee5\u5f00\u53d1\u8005\u90fd\u91c7\u7528\u5168\u90e8\u5355\u8bcd\u5927\u5199\u7684\u89c4\u8303\u6765\u547d\u540d\u8fd9\u4e2a\u7a0b\u5e8f\u751f\u547d\u5468\u671f\u4e2d\u90fd\u4e0d\u4f1a\u6539\u53d8\u7684\u53d8\u91cf\uff0c\u5982\uff1a<\/p>\n<div class=\"zxx_code\">\n<pre>\n<span class=\"cg\">\/\/ \u73cd\u8d35\u5e38\u6570\uff0c\u53ea\u53ef\u8fdc\u89c2<\/span>\nvar PI = 3.14,\n    MAX_WIDTH = 800;\n<\/pre>\n<\/div>\n<p>\u8fd8\u6709\u53e6\u5916\u4e00\u4e2a\u5b8c\u5168\u5927\u5199\u7684\u60ef\u4f8b\uff1a\u5168\u5c40\u53d8\u91cf\u540d\u5b57\u5168\u90e8\u5927\u5199\u3002\u5168\u90e8\u5927\u5199\u547d\u540d\u5168\u5c40\u53d8\u91cf\u53ef\u4ee5\u52a0\u5f3a\u51cf\u5c0f\u5168\u5c40\u53d8\u91cf\u6570\u91cf\u7684\u5b9e\u8df5\uff0c\u540c\u65f6\u8ba9\u5b83\u4eec\u6613\u4e8e\u533a\u5206\u3002<\/p>\n<p>\u53e6\u5916\u4e00\u79cd\u4f7f\u7528\u89c4\u8303\u6765\u6a21\u62df\u529f\u80fd\u7684\u662f\u79c1\u6709\u6210\u5458\u3002\u867d\u7136\u53ef\u4ee5\u5728JavaScript\u4e2d\u5b9e\u73b0\u771f\u6b63\u7684\u79c1\u6709\uff0c\u4f46\u662f\u5f00\u53d1\u8005\u53d1\u73b0\u4ec5\u4ec5\u4f7f\u7528\u4e00\u4e2a\u4e0b\u5212\u7ebf\u524d\u7f00\u6765\u8868\u793a\u4e00\u4e2a\u79c1\u6709\u5c5e\u6027\u6216\u65b9\u6cd5\u4f1a\u66f4\u5bb9\u6613\u4e9b\u3002\u8003\u8651\u4e0b\u9762\u7684\u4f8b\u5b50\uff1a<\/p>\n<div class=\"zxx_code\">\n<pre>\nvar person = {\n    getName: function () {\n        return this._getFirst() + ' ' + this._getLast();\n    },\n\n    _getFirst: function () {\n        <span class=\"cg\">\/\/ ...<\/span>\n    },\n    _getLast: function () {\n        <span class=\"cg\">\/\/ ...<\/span>\n    }\n};\n<\/pre>\n<\/div>\n<p>\u5728\u6b64\u4f8b\u4e2d\uff0c<code>getName()<\/code>\u5c31\u8868\u793a\u516c\u5171\u65b9\u6cd5\uff0c\u90e8\u5206\u7a33\u5b9a\u7684API\u3002\u800c<code>_getFirst()<\/code>\u548c<code>_getLast()<\/code>\u5219\u8868\u660e\u4e86\u79c1\u6709\u3002\u5b83\u4eec\u4ecd\u7136\u662f\u6b63\u5e38\u7684\u516c\u5171\u65b9\u6cd5\uff0c\u4f46\u662f\u4f7f\u7528\u4e0b\u5212\u7ebf\u524d\u7f00\u6765\u8b66\u544aperson\u5bf9\u8c61\u7684\u4f7f\u7528\u8005\u8fd9\u4e9b\u65b9\u6cd5\u5728\u4e0b\u4e00\u4e2a\u7248\u672c\u4e2d\u65f6\u4e0d\u80fd\u4fdd\u8bc1\u5de5\u4f5c\u7684\uff0c\u662f\u4e0d\u80fd\u76f4\u63a5\u4f7f\u7528\u7684\u3002\u6ce8\u610f\uff0cJSLint\u6709\u4e9b\u4e0d\u9e1f\u4e0b\u5212\u7ebf\u524d\u7f00\uff0c\u9664\u975e\u4f60\u8bbe\u7f6e\u4e86noman\u9009\u9879\u4e3a:false\u3002<\/p>\n<p>\u4e0b\u9762\u662f\u4e00\u4e9b\u5e38\u89c1\u7684_private\u89c4\u8303\uff1a<\/p>\n<ul id=\"ul\">\n<li>\u4f7f\u7528\u5c3e\u4e0b\u5212\u7ebf\u8868\u793a\u79c1\u6709\uff0c\u5982name_\u548cgetElements_()<\/li>\n<li>\u4f7f\u7528\u4e00\u4e2a\u4e0b\u5212\u7ebf\u524d\u7f00\u8868_protected\uff08\u4fdd\u62a4\uff09\u5c5e\u6027\uff0c\u4e24\u4e2a\u4e0b\u5212\u7ebf\u524d\u7f00\u8868\u793a__private \uff08\u79c1\u6709\uff09\u5c5e\u6027<\/li>\n<li>Firefox\u4e2d\u4e00\u4e9b\u5185\u7f6e\u7684\u53d8\u91cf\u5c5e\u6027\u4e0d\u5c5e\u4e8e\u8be5\u8bed\u8a00\u7684\u6280\u672f\u90e8\u5206\uff0c\u4f7f\u7528\u4e24\u4e2a\u524d\u4e0b\u5212\u7ebf\u548c\u4e24\u4e2a\u540e\u4e0b\u5212\u7ebf\u8868\u793a\uff0c\u5982\uff1a__proto__\u548c__parent__\u3002<\/li>\n<\/ul>\n<h3>\u6ce8\u91ca(Writing Comments)<\/h3>\n<p>\u4f60\u5fc5\u987b\u6ce8\u91ca\u4f60\u7684\u4ee3\u7801\uff0c\u5373\u4f7f\u4e0d\u4f1a\u6709\u5176\u4ed6\u4eba\u5411\u4f60\u4e00\u6837\u63a5\u89e6\u5b83\u3002\u901a\u5e38\uff0c\u5f53\u4f60\u6df1\u5165\u7814\u7a76\u4e00\u4e2a\u95ee\u9898\uff0c\u4f60\u4f1a\u5f88\u6e05\u695a\u7684\u77e5\u9053\u8fd9\u4e2a\u4ee3\u7801\u662f\u5e72\u561b\u7528\u7684\uff0c\u4f46\u662f\uff0c\u5f53\u4f60\u4e00\u5468\u4e4b\u540e\u518d\u56de\u6765\u770b\u7684\u65f6\u5019\uff0c\u60f3\u5fc5\u4e5f\u8981\u8017\u6389\u4e0d\u5c11\u8111\u7ec6\u80de\u53bb\u641e\u660e\u767d\u5230\u5e95\u600e\u4e48\u5de5\u4f5c\u7684\u3002<\/p>\n<p>\u5f88\u663e\u7136\uff0c\u6ce8\u91ca\u4e0d\u80fd\u8d70\u6781\u7aef\uff1a\u6bcf\u4e2a\u5355\u72ec\u53d8\u91cf\u6216\u662f\u5355\u72ec\u4e00\u884c\u3002\u4f46\u662f\uff0c\u4f60\u901a\u5e38\u5e94\u8be5\u8bb0\u5f55\u6240\u6709\u7684\u51fd\u6570\uff0c\u5b83\u4eec\u7684\u53c2\u6570\u548c\u8fd4\u56de\u503c\uff0c\u6216\u662f\u4efb\u4f55\u4e0d\u5bfb\u5e38\u7684\u6280\u672f\u548c\u65b9\u6cd5\u3002\u8981\u60f3\u5230\u6ce8\u91ca\u53ef\u4ee5\u7ed9\u4f60\u4ee3\u7801\u672a\u6765\u7684\u9605\u8bfb\u8005\u4ee5\u8bf8\u591a\u63d0\u793a\uff1b\u9605\u8bfb\u8005\u9700\u8981\u7684\u662f\uff08\u4e0d\u8981\u8bfb\u592a\u591a\u7684\u4e1c\u897f\uff09\u4ec5\u6ce8\u91ca\u548c\u51fd\u6570\u5c5e\u6027\u540d\u6765\u7406\u89e3\u4f60\u7684\u4ee3\u7801\u3002\u4f8b\u5982\uff0c\u5f53\u4f60\u6709\u4e94\u516d\u884c\u7a0b\u5e8f\u6267\u884c\u7279\u5b9a\u7684\u4efb\u52a1\uff0c\u5982\u679c\u4f60\u63d0\u4f9b\u4e86\u4e00\u884c\u4ee3\u7801\u76ee\u7684\u4ee5\u53ca\u4e3a\u4ec0\u4e48\u5728\u8fd9\u91cc\u7684\u63cf\u8ff0\u7684\u8bdd\uff0c\u9605\u8bfb\u8005\u5c31\u53ef\u4ee5\u76f4\u63a5\u8df3\u8fc7\u8fd9\u6bb5\u7ec6\u8282\u3002\u6ca1\u6709\u786c\u6027\u89c4\u5b9a\u6ce8\u91ca\u4ee3\u7801\u6bd4\uff0c\u4ee3\u7801\u7684\u67d0\u4e9b\u90e8\u5206\uff08\u5982\u6b63\u5219\u8868\u8fbe\u5f0f\uff09\u53ef\u80fd\u6ce8\u91ca\u8981\u6bd4\u4ee3\u7801\u591a\u3002<\/p>\n<blockquote><p>\n\u6700\u91cd\u8981\u7684\u4e60\u60ef\uff0c\u7136\u800c\u4e5f\u662f\u6700\u96be\u9075\u5b88\u7684\uff0c\u5c31\u662f\u4fdd\u6301\u6ce8\u91ca\u7684\u53ca\u65f6\u66f4\u65b0\uff0c\u56e0\u4e3a\u8fc7\u65f6\u7684\u6ce8\u91ca\u6bd4\u6ca1\u6709\u6ce8\u91ca\u66f4\u52a0\u7684\u8bef\u5bfc\u4eba\u3002\n<\/p><\/blockquote>\n<h3>\u5173\u4e8e\u4f5c\u8005\uff08About the Author \uff09<\/h3>\n<p>Stoyan Stefanov\u662fYahoo!web\u5f00\u53d1\u4eba\u5458\uff0c\u591a\u4e2aO'Reilly\u4e66\u7c4d\u7684\u4f5c\u8005\u3001\u6295\u7a3f\u8005\u548c\u6280\u672f\u8bc4\u5ba1\u3002\u4ed6\u7ecf\u5e38\u5728\u4f1a\u8bae\u548c\u4ed6\u7684\u535a\u5ba2<a target=\"_blank\" href=\"www.phpied.com\">www.phpied.com<\/a>\u4e0a\u53d1\u8868web\u5f00\u53d1\u4e3b\u9898\u7684\u6f14\u8bb2\u3002Stoyan\u8fd8\u662fsmush.it\u56fe\u7247\u4f18\u5316\u5de5\u5177\u7684\u521b\u9020\u8005\uff0cYUI\u8d21\u732e\u8005\uff0c\u96c5\u864e\u6027\u80fd\u4f18\u5316\u5de5\u5177YSlow 2.0\u7684\u67b6\u6784\u8bbe\u8ba1\u5e08\u3002<\/p>\n<p><span class=\"s\">\/\/zxx: \u4ee5\u4e0a\u5c31\u662f\u7ffb\u8bd1\u7684\u5168\u90e8\u5185\u5bb9\uff0c\u591f\u957f\u5427~~<img decoding=\"async\" src=\"http:\/\/a.xnimg.cn\/imgpro\/emotions\/tie\/9.gif?ver=1\" title=\"\u53ef\u7231\" alt=\"\u53ef\u7231\" emotion=\"(\u53ef\u7231)\" \/><\/span><\/p>\n<h3>\u8bd1\u5236\u4eba\u5458\u7ed3\u8bed<\/h3>\n<p>\u5e9f\u8bdd\u4e0d\u591a\u8bf4\u3002\u7ffb\u8bd1\u6c34\u5e73\u62d9\u52a3\uff0c\u6240\u4ee5\u6587\u4e2d\u96be\u514d\u4f1a\u6709\u7ffb\u8bd1\u4e0d\u51c6\u786e\u7684\u5730\u65b9\uff0c\u6211\u7238\u4e0d\u662f\u674e\u521a\uff0c\u6240\u4ee5\u8981\u662f\u7ffb\u8bd1\u6216\u8868\u8ff0\u6709\u9519\u8bf7\u653e\u5fc3\u5927\u80c6\u5730\u5927\u529b\u6307\u6b63\uff0c\u4e0d\u751a\u611f\u8c22\u3002<\/p>\n<p>\u672c\u6587\u4e3a\u539f\u521b\u6587\u7ae0\uff0c\u8f6c\u8f7d\u8bf7\u6ce8\u660e\u6765\u81ea<a href=\"http:\/\/www.zhangxinxu.com\/\">\u5f20\u946b\u65ed-\u946b\u7a7a\u95f4-\u946b\u751f\u6d3b<\/a>[<a href=\"http:\/\/www.zhangxinxu.com\/\">http:\/\/www.zhangxinxu.com<\/a>]<br \/>\n\u672c\u6587\u5730\u5740\uff1a<a href=\"http:\/\/www.zhangxinxu.com\/wordpress\/?p=1173\">http:\/\/www.zhangxinxu.com\/wordpress\/?p=1173<\/a><\/p>\n<p>\uff08\u672c\u7bc7\u5b8c\uff09<\/p>\n","protected":false},"excerpt":{"rendered":"<p><a href=\"http:\/\/www.zhangxinxu.com\/wordpress\/?p=1173\"><img loading=\"lazy\" decoding=\"async\" title=\"\u70b9\u51fb\u8fdb\u5165'\u9ad8\u8d28\u91cfJavaScript\u4ee3\u7801\u4e66\u5199\u57fa\u672c\u8981\u70b9'\u6b63\u6587\" src=\"http:\/\/image.zhangxinxu.com\/image\/blog\/201010\/js-hight-quality.jpg\" width=\"550\" height=\"151\" class=\"imgpad mb10\" \/><\/a><br \/>\n\u624d\u534e\u6a2a\u6ea2\u7684Stoyan Stefanov\uff0c\u5728\u4ed6\u5199\u7684\u7531O\u2019Reilly\u521d\u7248\u7684\u65b0\u4e66\u300aJavaScript Patterns\u300b(JavaScript\u6a21\u5f0f)\u4e2d\uff0c\u6211\u60f3\u8981\u662f\u4e3a\u6211\u4eec\u7684\u8bfb\u8005\u8d21\u732e\u5176\u6458\u8981\uff0c\u90a3\u4f1a\u662f\u4ef6\u5f88\u7f8e\u5999\u7684\u4e8b\u60c5\u3002\u5177\u4f53\u4e00\u70b9\u5c31\u662f\u7f16\u5199\u9ad8\u8d28\u91cfJavaScript\u7684\u4e00\u4e9b\u8981\u7d20\uff0c\u4f8b\u5982\u907f\u514d\u5168\u5c40\u53d8\u91cf\uff0c\u4f7f\u7528\u5355\u53d8\u91cf\u58f0\u660e\uff0c\u5728\u5faa\u73af\u4e2d\u9884\u7f13\u5b58length(\u957f\u5ea6)\uff0c\u9075\u5faa\u4ee3\u7801\u9605\u8bfb\uff0c\u4ee5\u53ca\u66f4\u591a\u3002<\/p>\n<p>\u6b64\u6458\u8981\u4e5f\u5305\u62ec\u4e00\u4e9b\u4e0e\u4ee3\u7801\u4e0d\u592a\u76f8\u5173\u7684\u4e60\u60ef\uff0c\u4f46\u5bf9\u6574\u4f53\u4ee3\u7801\u7684\u521b\u5efa\u606f\u606f\u76f8\u5173\uff0c\u5305\u62ec\u64b0\u5199API\u6587\u6863\u3001\u6267\u884c\u540c\u884c\u8bc4\u5ba1\u4ee5\u53ca\u8fd0\u884cJSLint\u3002\u8fd9\u4e9b\u4e60\u60ef\u548c\u6700\u4f73\u505a\u6cd5\u53ef\u4ee5\u5e2e\u52a9\u4f60\u5199\u51fa\u66f4\u597d\u7684\uff0c\u66f4\u6613\u4e8e\u7406\u89e3\u548c\u7ef4\u62a4\u7684\u4ee3\u7801\uff0c\u8fd9\u4e9b\u4ee3\u7801\u5728\u51e0\u4e2a\u6708\u6216\u662f\u51e0\u5e74\u4e4b\u540e\u518d\u56de\u8fc7\u5934\u770b\u770b\u4e5f\u662f\u4f1a\u89c9\u5f97\u5f88\u81ea\u8c6a\u7684\u3002<\/p>\n<p>\u5177\u4f53\u5185\u5bb9\u8fd9\u91cc\u4e0d\u591a\u8bf4\uff0c\u603b\u4e4b\uff0c\u6211\u76f8\u4fe1\u65e0\u8bba\u4f60\u662f\u65b0\u624b\u8fd8\u662f\u6709\u4e00\u5b9a\u7ecf\u9a8c\u7684JavaScript\u5f00\u53d1\u4eba\u5458\uff0c\u90fd\u4f1a\u5bf9\u60a8\u7684\u8ba4\u8bc6\u548c\u5b66\u4e60\u63d0\u4f9b\u5e2e\u52a9\u7684\u3002<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[198],"tags":[13,504,505,508,503,493,509,510,150,513,514,511,512,223,507],"_links":{"self":[{"href":"https:\/\/www.zhangxinxu.com\/wordpress\/wp-json\/wp\/v2\/posts\/1173"}],"collection":[{"href":"https:\/\/www.zhangxinxu.com\/wordpress\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.zhangxinxu.com\/wordpress\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.zhangxinxu.com\/wordpress\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.zhangxinxu.com\/wordpress\/wp-json\/wp\/v2\/comments?post=1173"}],"version-history":[{"count":0,"href":"https:\/\/www.zhangxinxu.com\/wordpress\/wp-json\/wp\/v2\/posts\/1173\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.zhangxinxu.com\/wordpress\/wp-json\/wp\/v2\/media?parent=1173"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.zhangxinxu.com\/wordpress\/wp-json\/wp\/v2\/categories?post=1173"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.zhangxinxu.com\/wordpress\/wp-json\/wp\/v2\/tags?post=1173"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}