获取url地址中的问号参

var getUrlParam = function (name) {
         var reg = new RegExp("(^|&)" + name + "=([^&]*)(&|$)");
         var r = window.location.search.substr(1).match(reg);
         if (r != null) return decodeURI(r[2]); return null;
     }

alert(getUrlParam('id'));