js判断浏览器类型

if(window.navigator.userAgent.toLowerCase().indexOf("msie") > 0){

    return “IE”;

}

if(window.navigator.userAgent.toLowerCase().indexOf("msie 8.0") > -1){

    return “IE 8”;

}

firefox判断应该是ua.match(/firefox[/s](d+)/);

var isIE=!!window.ActiveXObject; 
var isIE6=isIE&&!window.XMLHttpRequest; 
var isIE8=isIE&&!!document.documentMode; 
var isIE7=isIE&&!isIE6&&!isIE8; 
if (isIE){ 
if (isIE6){ 
alert("ie6"); 
}else if (isIE8){ 
alert("ie8"); 
}else if (isIE7){ 
alert("ie7"); 
} 
} 

f(navigator.appName == "Microsoft Internet Explorer" && navigator.appVersion.match(/6./i)=="6."){ 
alert("IE 6"); 
} 
else if(navigator.appName == "Microsoft Internet Explorer" && navigator.appVersion.match(/7./i)=="7."){ 
alert("IE 7"); 
} 
else if(navigator.appName == "Microsoft Internet Explorer" && navigator.appVersion.match(/8./i)=="8."){ 
alert("IE 8"); 
} 
else if(navigator.appName == "Microsoft Internet Explorer" && navigator.appVersion.match(/9./i)=="9."){ 
alert("IE 9"); 
} 

if(navigator.userAgent.indexOf("Opera") != -1) { 
alert('Opera'); 
} 
else if(navigator.userAgent.indexOf("MSIE") != -1) { 
alert('Internet Explorer'); 
} 
else if(navigator.userAgent.indexOf("Firefox") != -1) { 
alert('Firefox'); 
} 
else if(navigator.userAgent.indexOf("Netscape") != -1) { 
alert('Netscape'); 
} 
else if(navigator.userAgent.indexOf("Safari") != -1) { 
alert('Safari'); 
} 
else{ 
alert('无法识别的浏览器。'); 
}