主机屋免费空间在网页中动态插入free_ad.js；此举让我心寒
以下这段代码是主机屋在网页的首页最后动态加载的代码<script src=http://www.zhujiwu.com/free_ad.js></script>：

其内容如下，请高手帮忙分析以下干什么的：

//该代码为主机屋统计代码，不会对您的网站造成任何影响。

var a4275tf="51la";var a4275pu="";var a4275pf="51la";var a4275su=window.location;var a4275sf=document.referrer;var a4275of="";var a4275op="";var a4275ops=1;var a4275ot=1;var a4275d=new Date();var a4275color="";if (navigator.appName=="Netscape"){a4275color=screen.pixelDepth;} else {a4275color=screen.colorDepth;}
try{a4275tf=top.document.referrer;}catch(e){}
try{a4275pu =window.parent.location;}catch(e){}
try{a4275pf=window.parent.document.referrer;}catch(e){}
try{a4275ops=document.cookie.match(new RegExp("(^| )AJSTAT_ok_pages=([^;]*)(;|$)"));a4275ops=(a4275ops==null)?1: (parseInt(unescape((a4275ops)[2]))+1);var a4275oe =new Date();a4275oe.setTime(a4275oe.getTime()+60*60*1000);document.cookie="AJSTAT_ok_pages="+a4275ops+ ";path=/;expires="+a4275oe.toGMTString();a4275ot=document.cookie.match(new RegExp("(^| )AJSTAT_ok_times=([^;]*)(;|$)"));if(a4275ot==null){a4275ot=1;}else{a4275ot=parseInt(unescape((a4275ot)[2])); a4275ot=(a4275ops==1)?(a4275ot+1):(a4275ot);}a4275oe.setTime(a4275oe.getTime()+365*24*60*60*1000);document.cookie="AJSTAT_ok_times="+a4275ot+";path=/;expires="+a4275oe.toGMTString();}catch(e){}
a4275of=a4275sf;if(a4275pf!=="51la"){a4275of=a4275pf;}if(a4275tf!=="51la"){a4275of=a4275tf;}a4275op=a4275pu;try{lainframe}catch(e){a4275op=a4275su;}document.write('<img style="width:0px;height:0px" src="http://web.51.la/go.asp?svid=32&id=3394275&tpages='+a4275ops+'&ttimes='+a4275ot+'&tzone='+(0-a4275d.getTimezoneOffset()/60)+'&tcolor='+a4275color+'&sSize='+screen.width+','+screen.height+'&referrer='+escape(a4275of)+'&vpage='+escape(a4275op)+'" />');

------解决方案--------------------
主机屋的免费虚拟主机是有广告的，你会发现在你自己的某些网页的下方会有“本站由主机屋提供虚拟主机支持”的超级链接。
------解决方案--------------------
对付这种网站就要停止使用