如何从Codeigniter中的给定地址获取纬度和经度

This is my jQuery code:

      $(document).ready(function(){

           $("#landmark").focusout(function(){
           var geocoder = new google.maps.Geocoder();
           var address = $("#landmark").val();
           if(address!="")
           {
           geocoder.geocode( { 'address': address}, function(results, 
           status) {

             if (status == google.maps.GeocoderStatus.OK) {
               var latitude = results[0].geometry.location.lat();
               var longitude = results[0].geometry.location.lng();
               $("#lat").val(latitude);
               $("#longi").val(longitude); 
               }   
           });
           }
         });
       });

This doesn't work with Codeigniter - do I need to add some library files in Codeigniter?