// Put all of this in a closure
(function($){


// Do what you will within this block since the DOM is now ready

$(document).bind('ready', function() {
    	
    	
    //Add selected class to appropriate navigation tab
    $(function(){
       var itemID = $.getURLParam("Itemid");

       if ($.getURLParam("Itemid")==null) {
          $('div#header_img').addClass('itemidnull');
        }
        else {
         $('div#header_img').addClass('itemid'+ itemID);
          //  alert("itemid =" + itemID);
        }
     });
     
   
});

})(jQuery); // Pass in jQuery so we can safely use the $ alias for jQuery within this block