javascript 判断用户离开当前页面或封锁浏览器并给出提示
日期：2014-05-16 浏览次数：20360 次
<script type="text/javascript">
function closeIt()
{
? return "Any string value here forces a dialog box to \n" +?
? ? ? ? ?"appear before closing the window.";
}
window.onbeforeunload = closeIt;
</script>
或者
<script type="text/javascript">
window.onbeforeunload?= function() {return 'Sure to leave?';};
</script>
可参见：http://msdn.microsoft.com/en-us/library/ms536907(VS.85).aspx
同一页面可提示可不提示：<html>
<body>
<a href="javascript:alert('Hello World!');">Warning</a><br/>
<a onclick="NoPrompt();" href="http://www.baidu.com">No Warning</a>
<script>// Allow the user to be warned by default.
var allowPrompt = true;
window.onbeforeunload = WarnUser;
function WarnUser()
{
if(allowPrompt)
{
event.returnValue = "You have made changes. They will be lost if you continue.";
}
else
{
// Reset the flag to its default value.
allowPrompt = true;
}
