保存一段代码，留着以后备用

HTML:

<script type="text/javascript">
function checkBrowser() 
{ 
this.ver=navigator.appVersion 
this.dom=document.getElementById?1:0 
this.ie6=(this.ver.indexOf("MSIE 6")>-1 && this.dom)?1:0; 
this.ie5=(this.ver.indexOf("MSIE 5")>-1 && this.dom)?1:0; 
this.ie4=(document.all && !this.dom)?1:0; 
this.ns5=(this.dom && parseInt(this.ver) >= 5) ?1:0; 
this.ns4=(document.layers && !this.dom)?1:0; 
this.mac=(this.ver.indexOf('Mac') > -1) ?1:0; 
this.ope=(navigator.userAgent.indexOf('Opera')>-1); 
this.ie=(this.ie6 || this.ie5 || this.ie4) 
this.ns=(this.ns4 || this.ns5) 
this.bw=(this.ie6 || this.ie5 || this.ie4 || this.ns5 || this.ns4 || this.mac || this.ope) 
this.nbw=(!this.bw) 
return this; 
} 
var s=checkBrowser();
if(s.ns) 
{
   alert('系统检测到您现在使用的是FireFox类型的浏览器， \n 为能得到更好的播放效果， 请您切换到 IE 浏览器下使用.');
   window.close();
}
</script>