how can i trigger event when hidden div get focus in jQuery?

In a tabb design If there are multiple hidden div how can i trigger event when hidden div get focus using jquery. I tried "focus" but thats for form controls. please suggest

From stackoverflow

• You could supply a callback to the show() method, provided you are the one making that call.

  $('#tab1').show('fast', function(){
      // do something now that it is showing
  });
  

• It is difficult to focus hidden field. But I suggest to use opacity as alternative if your existing DIVs code is editable. You can do it something like this:

  HTML:

  <div id="hiddendiv" style="height:'200';width:'200'">This is hidden DIV</div>
  

  jQuery:

  $('#hiddendiv').stop().animate({ opacity: 0.0 }, 500);
  
  $('#hiddendiv').live('mouseenter', function(){
      $('#hiddendiv').stop().animate({ opacity: 1.0 }, 500);
  });
  

  Demo