把URL参数解析为一个对象

        function parseQueryString(url) {
           var params = {};
           var arr = url.split("?");
           if (arr.length <= 1) {
              return params;
           }
           arr = arr[1].split("&");
           for(var i = 0, l = arr.length; i < l; i++) {
              var a = arr[i].split("=");
              params[a[0]] = a[1];
           }
           return params;
        }