Como carrego Individual Div sem carregar a página inteira e mostrar o status de carregamento?

<div id="displayDiv" style="display: none">
  <img id="loadingGif" src="loadingGif" style="display:none"; />
  <div id="actualContent" style="display:none" />
</div>
<input type="button" id="loadButton" />

<script type="text/javascript">
   $(document).ready( onDocumentReady); // this runs before page load

   function onDocumentReady()
   {
      $('#loadButton').click( onLoadClick ); //assign action on button click
   }   

   function onLoadClick()
   {
       $('#loadingGif').show(); // show the loading gif. It won't show as long as it's parent is hidden
       $('#actualContent').hide(); // hide the actual content of the response;
       $('#displayDiv').show(); // display the div
       $.get("test.php", onRequestComplete ); // make the ajax request to the stand alone PHP file
      //so as long as the content loads, the loading gif will show;
   }

   function onRequestComplete( data )
   {
      $('#loadingGif').hide();
      $('#actualContent').html( data );
      $('#actualContent').show();
   }
</script>