js 拦截 窗体关闭事件

<script type="text/javascript">   
<!--     
    window.onbeforeunload = onbeforeunload_handler;
    window.onunload = onunload_handler;
    function onbeforeunload_handler() {
        var warning = "退出吗?";
        return warning;
    }

    function onunload_handler() {
        var warning = "谢谢光临";
        alert(warning);
    }
    // -->   
</script> 

js 拦截 窗体关闭事件

原文：http://www.cnblogs.com/ifreesoft/p/3967039.html