var lng,lat;
var address = "静安寺";
var url = "http://api.map.baidu.com/geocoder/v2/?address="+address+"&output=json&ak=你的AK值&city=上海";

$.ajax({
    url: url,dataType: "jsonp",jsonp: "callback",success: function (data) {
         lat = data.result.location.lat;
         lng = data.result.location.lng;
    }
})