var P_id=request($("a").attr("href"),"id");
var P_pageid=request($("a").attr("href"),"page");

//根据QueryString参数名称获取值
function request(winhref, para) {
    var subflag=winhref.lastIndexOf('?');
    var params = winhref.substring(subflag + 1).split('&');
    for (var i = 0; i < params.length; i++) {
        var pars = params[i].split('=');
        if (pars[0] == para) {
            if (pars.length > 1) {
                return pars[1];
            }
            else {
                return "";
            }
        }
    }
    return "";
}

------解决方案--------------------

function urlParam(name,url){
 var results = new RegExp('[\\?&]' + name + '=([^&#]*)').exec(url);
 if (!results) { return null; }
 return results[1] || null;
}
var url="/xxx/xxx/xx?id=519&page=1";
alert(urlParam('id',url))
alert(urlParam('page',url))

------解决方案--------------------
id = url.split('&')[0].split('=')[1];
page = url.split('&')[1].split('=')[1]