ajax load null problem

ajax load null problem

I am loading html that is generated from a php controller model. It is all working great other than there is a weird null being printed on the bottom of the html. I made sure that it is definitely the ajax load printing the null on the bottom. I am new to jquery and cannot figure this out. What is causing this?

Here is my functions:        
  1. function load_messages() {
                $('#messageajax').load("dashboard/get_messages",function(){});
                }

    $(function() {
    $('#dialog').dialog({
    autoOpen: false,
    modal: true,
                            height:500,
    width: 500

    })
    $('#opener').click(function() {
                        $('#messageajax').html('<div id="loading">Loading messages, please wait..<br><img src="assets/img/ajax-loader.gif" alt="loading.." /></div>');
                           //setTimeout('load_messages()', 10000);
                            load_messages();
    $('#dialog').dialog('open');
    return false;
    });