var isOpera;
var isIE;
var isFF;
var isSafari;
var isChrome;
function myBrowser(){  
	var userAgent = navigator.userAgent; //取得浏览器的userAgent字符串  
	isOpera = userAgent.indexOf("Opera") > -1; //判断是否Opera浏览器  
	isIE = userAgent.indexOf("compatible") > -1 && userAgent.indexOf("MSIE") > -1 && !isOpera ; //判断是否IE浏览器   
	isFF = userAgent.indexOf("Firefox") > -1 ; //判断是否Firefox浏览器  
	isSafari = userAgent.indexOf("Safari") > -1 && userAgent.indexOf("Chrome") < 1 ; //判断是否Safari浏览器  
	isChrome = userAgent.indexOf("Chrome") > -1 ; //判断是否Chrome浏览器  
	if(isIE){   
	   var IE5 = IE55 = IE6 = IE7 = IE8 = false;  
	   var reIE = new RegExp("MSIE (\\d+\\.\\d+);");  
	   reIE.test(userAgent);  
	   var fIEVersion = parseFloat(RegExp["$1"]);  
	  
	   IE55 = fIEVersion == 5.5 ;  
	   IE6 = fIEVersion == 6.0 ;  
	   IE7 = fIEVersion == 7.0 ;  
	   IE8 = fIEVersion == 8.0 ;  
	  
	   if(IE55){ return "IE55"; }  
	   if(IE6){ return "IE6"; }  
	   if(IE7){ return "IE7"; }  
	   if(IE8){ return "IE8"; }  
	}  

}
myBrowser();