JavaScript判断浏览器类型与版本号

<title>用JavaScript判断浏览器类型及版本号</title>
<script>
window["MzBrowser"]={};(function()
{
if(MzBrowser.platform) return;
var ua = window.navigator.userAgent;
MzBrowser.platform = window.navigator.platform;

MzBrowser.firefox = ua.indexOf("Firefox")>0;
MzBrowser.opera = typeof(window.opera)=="object";
MzBrowser.ie = !MzBrowser.opera && ua.indexOf("MSIE")>0;
MzBrowser.mozilla = window.navigator.product == "Gecko";
MzBrowser.netscape= window.navigator.vendor=="Netscape";
MzBrowser.safari= ua.indexOf("Safari")>-1;

if(MzBrowser.firefox) var re = /Firefox(\s|\/)(\d+(\.\d+)?)/;
else if(MzBrowser.ie) var re = /MSIE( )(\d+(\.\d+)?)/;
else if(MzBrowser.opera) var re = /Opera(\s|\/)(\d+(\.\d+)?)/;
else if(MzBrowser.netscape) var re = /Netscape(\s|\/)(\d+(\.\d+)?)/;
else if(MzBrowser.safari) var re = /Version(\/)(\d+(\.\d+)?)/;
else if(MzBrowser.mozilla) var re = /rv(\:)(\d+(\.\d+)?)/;

if("undefined"!=typeof(re)&&re.test(ua))
MzBrowser.version = parseFloat(RegExp.$2);
})(); // www.jiaochengji.com

function aa()
{
if(MzBrowser.ie)
{
alert('您的浏览器是IE');
}
if(MzBrowser.firefox)
{
alert('您的浏览是Firefox');
}
alert(MzBrowser.version);
}
aa();
</script>