js 正则，从url中取参数值

function getQueryString(name) { 
 var reg = new RegExp(name +"=([^&]*)");
     var r = window.location.href.match(reg);
     if(r!=null)return  unescape(r[1]); return null;
}

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