JavaScript获取Url参数

<script language="javascript" type="text/javascript"> 
//js获取url参数的function
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 
theurl=request("url"); 
if (theurl!=''){ 
location=theurl 
} 
</script>