JQuery 获取URL参数

jQuery.extend({
/**
* Returns get parameters. 返回获取参数。
*
* If the desired param does not exist, null will be returned  如果所需的参数不存在，将会返回null
*
* @例子 value = $.getURLParam("paramName");
*/ 
 getURLParam: function(strParamName,url){
      var strReturn = "";
      var strHref = url||window.location.href;
      var bFound=false;
      
      var cmpstring = strParamName + "=";
      var cmplen = cmpstring.length;

      if ( strHref.indexOf("?") > -1 ){
        var strQueryString = strHref.substr(strHref.indexOf("?")+1);
        var aQueryString = strQueryString.split("&");
        for ( var iParam = 0; iParam < aQueryString.length; iParam++ ){
          if (aQueryString[iParam].substr(0,cmplen)==cmpstring){
            var aParam = aQueryString[iParam].split("=");
            strReturn = aParam[1];
            bFound=true;
            break;
          }
          
        }
      }
      if (bFound==false) return null;
      return strReturn;
    }
});