The cited URL in turn calls more JS.
<script language=javascript src=add.jpg></script>
<script language="javascript" type="text/javascript" src="
http://js.users.51.la/1694158.js"></script>
<noscript><a href="
照常上量统计报告 - “我要啦”提供" target="_blank"><img alt="我要啦免费~ DF;计" src="
http://img.users.51.la/1694158.asp" style="border:none" /></a></noscript> ,
which in turn ... .
Quick guess - your machine has been infected by malware.