function loadScript(id, callback) {
        var queue = loadingMap[id] || (loadingMap[id] = []);
        queue.push(callback);

        //
        // load this script
        //
        var res = resMap[id] || {};
        var url = res.pkg
                    ? pkgMap[res.pkg].url
                    : (res.url || id);

        if (! (url in scriptsMap))  {
            scriptsMap[url] = true;

            var script = document.createElement('script');
            script.type = 'text/javascript';
            script.src = hao123.host + url;
            head.appendChild(script);
        }
    }
file: mod.js
ver: 1.0.3
auth: zhangjiachen@baidu.com
update: 11:48 2013/7/10