//main navigation
        preload('navhomeoff','images/nav/btn-home-off.png');
		preload('navhomeovr','images/nav/btn-home-ovr.png');
		preload('navhomeon','images/nav/btn-home-on.png');
		
        preload('navaboutoff','images/nav/btn-about-off.png');
		preload('navaboutovr','images/nav/btn-about-ovr.png');
		preload('navabouton','images/nav/btn-about-on.png');		
		
        preload('navtreatoff','images/nav/btn-treat-off.png');
		preload('navtreatovr','images/nav/btn-treat-ovr.png');
		preload('navtreaton','images/nav/btn-treat-on.png');		
		
        preload('navphotosoff','images/nav/btn-photos-off.png');
		preload('navphotosovr','images/nav/btn-photos-ovr.png');
		preload('navphotoson','images/nav/btn-photos-on.png');		
				
        preload('navstaffoff','images/nav/btn-staff-off.png');
		preload('navstaffovr','images/nav/btn-staff-ovr.png');
		preload('navstaffon','images/nav/btn-staff-on.png');			
		
        preload('navcontactoff','images/nav/btn-contact-off.png');
		preload('navcontactovr','images/nav/btn-contact-ovr.png');
		preload('navcontacton','images/nav/btn-contact-on.png');						

function preload(imgObj,imgSrc) {
	/*
		function to preload images
	*/
	if (document.images) {
		eval(imgObj+' = new Image()');
		eval(imgObj+'.src = "'+imgSrc+'"');
	}
}

function changeImage(imgName,imgObj,layer) {
	/*
		function to do rollovers of images
	*/
	if (document.images) {
		if (document.layers) {
			if (layer!=null){
				eval('document.layers.'+layer+'.document.images["'+imgName+'"].src = '+imgObj+'.src');
			} else {
				document.images[imgName].src = eval(imgObj+".src");
			}
		} else {
			document.images[imgName].src = eval(imgObj+".src");
		}
	}
}