各位大侠不要笑话，小弟啥技术不懂，因为急着用，特来求教
如何根据不同的浏览器来调用不同的js比如
ie6用户调用
<script src=1.js></script>
ie7、ie8用户调用
<script src=2.js></script>
firefox、chrome、Safari用户调用
<script src=3.js></script>
如何根据不同的浏览器来调用不同的js比如
ie6用户调用
<script src=1.js></script>
ie7、ie8用户调用
<script src=2.js></script>
firefox、chrome、Safari用户调用
<script src=3.js></script>
<html>
<head>
<script language="javascript">
window.onload = function(){
var script = document.getElementsByTagName('script')[1];
var Sys = {};
var ua = navigator.userAgent.toLowerCase();
if (window.ActiveXObject)
Sys.ie = ua.match(/msie ([\d.]+)/)[1]
else if (document.getBoxObjectFor)
Sys.firefox = ua.match(/firefox\/([\d.]+)/)[1]
else if (window.MessageEvent && !document.getBoxObjectFor)
Sys.chrome = ua.match(/chrome\/([\d.]+)/)[1]
else if (window.opera)
Sys.opera = ua.match(/opera.([\d.]+)/)[1]
else if (window.openDatabase)
Sys.safari = ua.match(/version\/([\d.]+)/)[1];
if(Sys.ie == '7.0' || Sys.id == '8.0'){
//ie7、ie8用户调用
script.setAttribute('src','2.js');
alert('aaa');
}else if(Sys.ie == '6.0'){
//ie6用户调用
script.setAttribute('src','1.js');
}else if(Sys.firefox != '' || Sys.chrome != '' || Sys.safari != '' && Sys.ie == ''){
//firefox、chrome、Safari用户调用
script.setAttribute('src','3.js');
alert('aaa');
}
};
</script>
<script type="text/javascript" src=""></script>
</head>
<body>
</body>
</html>