获取url参数

/*------------------------------获取url参数--------------------------------*/
function getParam(paramName)
{
    paramValue = "";
    isFound = false;
    if (this.location.search.indexOf("?") == 0 && this.location.search.indexOf("=")>1)
    {
        arrSource = unescape(this.location.search).substring(1,this.location.search.length).split("&");
        i = 0;
        while (i < arrSource.length && !isFound)
        {
            if (arrSource[i].indexOf("=") > 0)
            {
                 if (arrSource[i].split("=")[0].toLowerCase()==paramName.toLowerCase())
                 {
                    paramValue = arrSource[i].split("=")[1];
                    isFound = true;
                 }
            }
            i++;
        }   
    }
    return paramValue;
}