if (document.images) 
	{ 
	/* preload images */
	var map = new Image(600, 320);
	map.src = "../images/map.gif";

	var neuro = new Image(600, 320);
	neuro.src = "../images/map_neuro_on.gif";
	
	var neuroOff= new Image(600, 320);
	neuroOff.src = "../images/map.gif";
	
	var upham = new Image(600, 320);
	upham.src =  "../images/map_upham_on.gif";
	
	var uphamOff = new Image(600, 320);
	uphamOff.src =  "../images/map.gif";
	
	var courtyard = new Image(600, 320);
	courtyard.src = "../images/map_courtyard_on.gif";
	
	var courtyardOff = new Image(600, 320);
	courtyardOff.src = "../images/map.gif";
	
	var pavilion = new Image(600, 320);
	pavilion.src = "../images/map_pavilion_on.gif";
	
	var pavilionOff = new Image(600, 320);
	pavilionOff.src = "../images/map.gif";
	
	var waverley = new Image(600, 320);
	waverley.src = "../images/map_waverley_on.gif";
	
	var waverleyOff = new Image(600, 320);
	waverleyOff.src = "../images/map.gif";	
	
	// preload header images use rollover functions below
	
	var header_init = new Image(600, 95);
	header_init.src = "../images/map_header_off.gif";
	
	var header_new = new Image(600, 95);
	header_new.src = "../images/map_header_on.gif";
	
	}
	
// the rollover functions for the header only
	
  function on_nav(the_name, the_name2) 
  {
  	if (document.images)
  	{
  		document.images[the_name].src = eval(the_name + "_new.src");
  	}
  }
  function off_nav(the_name, the_name2)
  {
  	if (document.images)
  	{
  		document.images[the_name].src = eval(the_name + "_init.src");
  	}
 }