js获取url上的参数

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

console.log(getUrlParam("id"));