CODE EXAMPLE FOR JAVASCRIPT

show loader before page load

<div id="overlay">
     <img src="loading.gif" alt="Loading" />
     Loading...
</div>
<script type="text/javascript">
	$(window).load(function(){
   		// PAGE IS FULLY LOADED  
   		// FADE OUT YOUR OVERLAYING DIV
   		$('#overlay').fadeOut();
	});
</script>