javascript获取url参数的代码

<script language = javascript> 
function request(paras){ 
var url = location.href; 
var paraString = url.substring(url.indexOf("?")+1,url.length).split("&"); 
var paraObj = {} 
for (i=0; j=paraString[i]; i++){ 
paraObj[j.substring(0,j.indexOf("=")).toLowerCase()] = j.substring(j.indexOf("=")+1,j.length); 
} 
var returnValue = paraObj[paras.toLowerCase()]; 
if(typeof(returnValue)=="undefined"){ 
return ""; 
}else{ 
return returnValue; 
} 
} 
var theurl=request('url'); 
var theimg=request('img'); 
document.writeln("<a href='" + theurl + "' target=_blank><img src=" + theimg + " width=750 height=450 border=0></a>"); 
</script>