js 获取当前url的参数

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

    }

var url = 'http://www.haigoutong.com/index.php?id=7'

console.log(GetQueryString("id"))