function preload_nav() {
	var img1 = new Image();
	img1.src="images/nav_branding_on.gif";
	var img2 = new Image();
	img2.src="images/nav_financial_reports_on.gif";
	var img3 = new Image();
	img3.src="images/nav_brochures_on.gif";
	var img4 = new Image();
	img4.src="images/nav_foodservice_on.gif";
	var img5 = new Image();
	img5.src="images/nav_exhibits_on.gif";
}

preload_nav();


var section='';

function imgSwap(img,src) {
	if (img != section) {
  if (document[img]) document[img].src=src;
 }
}	

function setSection(img,src) {
	imgSwap(img,src);
	section = img;
}