<script language="javascript">
var url,a
function getQuery(name)
{
var reg = new RegExp("(^|&)"+name +"=([^&]*)(&|$)");
var r = window.location.search.substr(1).match(reg);
if(r!=null) return unescape(r[2]);return ""; //返回bbbb
}
url=getQuery("url");
a=getQuery("a");
document.write (a+url);
</script>