js判断浏览器的类型

<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);
	})(); 
	
	function demo()
	{
		var str;
		if(MzBrowser.ie)
		{
			str="您的浏览器是IE";
		}
		if(MzBrowser.firefox)
		{
			str="您的浏览是Firefox";
		}
	alert(str+MzBrowser.version);
}
demo();
</script>