此JavaScript必须适用于所有最新版本的浏览器:

//Detect Browser
var isOpera = !!window.opera || navigator.userAgent.indexOf(' OPR/') >= 0;
    // Opera 8.0+ (UA detection to detect Blink/v8-powered Opera)
var isFirefox = typeof InstallTrigger !== 'undefined';   // Firefox 1.0+
var isSafari = Object.prototype.toString.call(window.HTMLElement).indexOf('Constructor') > 0;
    // At least Safari 3+: "[object HTMLElementConstructor]"
var isChrome = !!window.chrome && !isOpera;              // Chrome 1+
var isIE = /*@cc_on!@*/false || !!document.documentMode; // At least IE6
var Host = window.location.host;


//Clear Basic Realm Authentication
if(isIE){
//IE
    document.execCommand("ClearAuthenticationCache");
    window.location = '/';
}
else if(isSafari)
{//Safari. but this works mostly on all browser except chrome
    (function(safeLocation){
        var outcome, u, m = "You should be logged out now.";
        // IE has a simple solution for it - API:
        try { outcome = document.execCommand("ClearAuthenticationCache") }catch(e){}
        // Other browsers need a larger solution - AJAX call with special user name - 'logout'.
        if (!outcome) {
            // Let's create an xmlhttp object
            outcome = (function(x){
                if (x) {
                    // the reason we use "random" value for password is 
                    // that browsers cache requests. changing
                    // password effectively behaves like cache-busing.
                    x.open("HEAD", safeLocation || location.href, true, "logout", (new Date()).getTime().toString())
                    x.send("");
                    // x.abort()
                    return 1 // this is **speculative** "We are done." 
                } else {
                    return
                }
            })(window.XMLHttpRequest ? new window.XMLHttpRequest() : ( window.ActiveXObject ? new ActiveXObject("Microsoft.XMLHTTP") : u )) 
        }
        if (!outcome) {
            m = "Your browser is too old or too weird to support log out functionality. Close all windows and restart the browser."
        }
        alert(m);
        window.location = '/';
        // return !!outcome
    })(/*if present URI does not return 200 OK for GET, set some other 200 OK location here*/)
}
else{
//Firefox,Chrome
    window.location = 'http://log:out@'+Host+'/';
}

让用户点击指向https://log:out@example.com/的链接。这将用无效的凭证覆盖现有的凭证;注销它们。

这是通过在URL中发送新的凭证来实现的。在本例中，user="log" password="out"。

bobince对这个问题的补充回答是…

使用Ajax，您可以将“注销”链接/按钮连接到Javascript函数。让这个函数发送带有错误用户名和密码的XMLHttpRequest。这应该会得到401。然后设置文档。位置返回到预登录页面。这样，用户将永远不会在注销期间看到额外的登录对话框，也不必记得输入错误的凭据。

下面是一个使用jQuery的非常简单的Javascript示例:

function logout(to_url) {
    var out = window.location.href.replace(/:\/\//, '://log:out@');

    jQuery.get(out).error(function() {
        window.location = to_url;
    });
}

此登录用户退出而不再次显示浏览器登录框，然后将其重定向到注销页面

使用会话ID (cookie) 使服务器上的会话ID失效 不接受会话id无效的用户

    function logout(secUrl, redirUrl) {
        if (bowser.msie) {
            document.execCommand('ClearAuthenticationCache', 'false');
        } else if (bowser.gecko) {
            $.ajax({
                async: false,
                url: secUrl,
                type: 'GET',
                username: 'logout'
            });
        } else if (bowser.webkit) {
            var xmlhttp = new XMLHttpRequest();
            xmlhttp.open("GET", secUrl, true);
            xmlhttp.setRequestHeader("Authorization", "Basic logout");
            xmlhttp.send();
        } else {
            alert("Logging out automatically is unsupported for " + bowser.name
                + "\nYou must close the browser to log out.");
        }
        setTimeout(function () {
            window.location.href = redirUrl;
        }, 200);
    }

我试着以以下方式使用上述方法。

?php
    ob_start();
    session_start();
    require_once 'dbconnect.php';

    // if session is not set this will redirect to login page
    if( !isset($_SESSION['user']) ) {
        header("Location: index.php");
        exit;
    }
    // select loggedin users detail
    $res=mysql_query("SELECT * FROM users WHERE userId=".$_SESSION['user']);
    $userRow=mysql_fetch_array($res);
?>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Welcome - <?php echo $userRow['userEmail']; ?></title>
<link rel="stylesheet" href="assets/css/bootstrap.min.css" type="text/css"  />
<link rel="stylesheet" href="style.css" type="text/css" />

    <script src="assets/js/bowser.min.js"></script>
<script>
//function logout(secUrl, redirUrl)
//bowser = require('bowser');
function logout(secUrl, redirUrl) {
alert(redirUrl);
    if (bowser.msie) {
        document.execCommand('ClearAuthenticationCache', 'false');
    } else if (bowser.gecko) {
        $.ajax({
            async: false,
            url: secUrl,
            type: 'GET',
            username: 'logout'
        });
    } else if (bowser.webkit) {
        var xmlhttp = new XMLHttpRequest();
        xmlhttp.open("GET", secUrl, true);
        xmlhttp.setRequestHeader("Authorization", "Basic logout");
        xmlhttp.send();
    } else {
        alert("Logging out automatically is unsupported for " + bowser.name
            + "\nYou must close the browser to log out.");
    }
    window.location.assign(redirUrl);
    /*setTimeout(function () {
        window.location.href = redirUrl;
    }, 200);*/
}


function f1()
    {
       alert("f1 called");
       //form validation that recalls the page showing with supplied inputs.    
    }
</script>
</head>
<body>

    <nav class="navbar navbar-default navbar-fixed-top">
      <div class="container">
        <div class="navbar-header">
          <button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#navbar" aria-expanded="false" aria-controls="navbar">
            <span class="sr-only">Toggle navigation</span>
            <span class="icon-bar"></span>
            <span class="icon-bar"></span>
            <span class="icon-bar"></span>
          </button>
          <a class="navbar-brand" href="http://www.codingcage.com">Coding Cage</a>
        </div>
        <div id="navbar" class="navbar-collapse collapse">
          <ul class="nav navbar-nav">
            <li class="active"><a href="http://www.codingcage.com/2015/01/user-registration-and-login-script-using-php-mysql.html">Back to Article</a></li>
            <li><a href="http://www.codingcage.com/search/label/jQuery">jQuery</a></li>
            <li><a href="http://www.codingcage.com/search/label/PHP">PHP</a></li>
          </ul>
          <ul class="nav navbar-nav navbar-right">

            <li class="dropdown">
              <a href="#" class="dropdown-toggle" data-toggle="dropdown" role="button" aria-haspopup="true" aria-expanded="false">
              <span class="glyphicon glyphicon-user"></span>&nbsp;Hi' <?php echo $userRow['userEmail']; ?>&nbsp;<span class="caret"></span></a>
              <ul class="dropdown-menu">
                <li><a href="logout.php?logout"><span class="glyphicon glyphicon-log-out"></span>&nbsp;Sign Out</a></li>
              </ul>
            </li>
          </ul>
        </div><!--/.nav-collapse -->
      </div>
    </nav> 

    <div id="wrapper">

    <div class="container">

        <div class="page-header">
        <h3>Coding Cage - Programming Blog</h3>
        </div>

        <div class="row">
        <div class="col-lg-12" id="div_logout">
        <h1 onclick="logout(window.location.href, 'www.espncricinfo.com')">MichaelA1S1! Click here to see log out functionality upon click inside div</h1>
        </div>
        </div>

    </div>

    </div>

    <script src="assets/jquery-1.11.3-jquery.min.js"></script>
    <script src="assets/js/bootstrap.min.js"></script>


</body>
</html>
<?php ob_end_flush(); ?>

但它只会把你重定向到新的位置。没有注销。