<body onbeforeunload="Close()" 或onunload="Close()" >
onbeforeunload 在 onunload 之前执行

function Close()
{
var ua = navigator.userAgent;
var ie = navigator.appName == "Microsoft Internet Explorer" ? true:false;
if (ie)
{
var IEversion=parseFloat(ua.substring(ua.indexOf("MSIE ")+5,ua.indexOf(";",ua.indexOf("MSIE "))));
if (IEversion< 5.5)
{
var str = '<object id=noTipClose classid="clsid:ADB880A6-D8FF-11CF-9377-00AA003B7A11">';
str += '<param name="Command" value="Close"></object>';
document.body.insertAdjacentHTML("beforeEnd", str);
document.all.noTipClose.Click();
} 
else
{
WindowClose();
}
} 
else
{
WindowClose();
}
}