Page Visibility(网页可见性) API与登录同步引导页实例页面

HTML代码：

<p id="loginInfo"></p>
                

JS代码：

(function() {
    if (typeof pageVisibility.hidden !== "undefined") {
        var eleLoginInfo = document.querySelector("#loginInfo");
        var funLoginInfo = function() {
            var username = localStorage.username || sessionStorage.username;
            if (username) {
                eleLoginInfo.innerHTML = '欢迎回来，<strong>' + username + '</strong>';
                sessionStorage.username = username;
            } else {
                eleLoginInfo.innerHTML = '您尚未登录，请<a target="_blank" href="'+ location.href.replace("-1.", "-2.") +'">登录</a>';
            }    
        }
        pageVisibility.visibilitychange(function() {
            if (!this.hidden) funLoginInfo();
        });
        
        funLoginInfo();
        
        // 页面关闭清除localStorage
        window.addEventListener("unload", function() {
            localStorage.removeItem("username");
        })
    } else {
        alert("弹框？？？没错，因为你的这个浏览器不支持Page Visibility API的啦！");    
    }
})();