// preload navigation images:
function preloadImages() {

	courses_over.src = "/images/nav-courses-over.gif";
	courses_off.src = "/images/nav-courses-off.gif";
	
	value_over.src = "/images/nav-value-over.gif";
	value_off.src = "/images/nav-value-off.gif";
	
	knowledge_over.src = "/images/nav-knowledge-over.gif";
	knowledge_off.src = "/images/nav-knowledge-off.gif";
	
	community_over.src = "/images/nav-community-over.gif";
	community_off.src = "/images/nav-community-off.gif";
	
	about_over.src = "/images/nav-about-over.gif";
	about_off.src = "/images/nav-about-off.gif";
	
	contact_over.src = "/images/nav-contact-over.gif";
	contact_off.src = "/images/nav-contact-off.gif";


}

if (document.images) {
   
   courses_over = new Image();
   courses_over.src = "/images/nav-courses-over.gif";
   courses_off = new Image();
   courses_off.src = "/images/nav-courses-off.gif";
   
   value_over = new Image();
   value_over.src = "/images/nav-value-over.gif";
   value_off = new Image();
   value_off.src = "/images/nav-value-off.gif";
   
   knowledge_over = new Image();
   knowledge_over.src = "/images/nav-knowledge-over.gif";
   knowledge_off = new Image();
   knowledge_off.src = "/images/nav-knowledge-off.gif";
   
   community_over = new Image();
   community_over.src = "/images/nav-community-over.gif";
   community_off = new Image();
   community_off.src = "/images/nav-community-off.gif";
   
   about_over = new Image();
   about_over.src = "/images/nav-about-over.gif";
   about_off = new Image();
   about_off.src = "/images/nav-about-off.gif";
   
   contact_over = new Image();
   contact_over.src = "/images/nav-contact-over.gif";
   contact_off = new Image();
   contact_off.src = "/images/nav-contact-off.gif";

   
} 

//GENERAL FUNCTIONS

function init(){

if (document.images) {
   spacerOn = new Image();
   spacerOn.src = "/images/spacer.gif";
  }

isNS4 = (document.layers) ? true : false;
isIE4 = (document.all && !document.getElementById) ? true : false;
isIE5 = (document.all && document.getElementById) ? true : false;
isNS6 = (!document.all && document.getElementById) ? true : false;

	
		if (isNS4){
		   layerRef = "document.layers";
		   styleSwitch="";
		}
		else if (isIE4) {
		   layerRef = "document.all";
		   styleSwitch=".style";
		}
		else if (isIE5 || isNS6) {
		   layerRef = "document.getElementById";
		   styleSwitch=".style";
		}		

		//wipeLeft('loadingBG');
		//hideLayer('header');
		//hideLayer('msg');
	}
	
function swapImage(imgName,newImage) {
   if (document.images) {
      eval('document.' + imgName + '.src = ' + newImage + '.src');
   }
}


function showLayer(layerName){
	var a = showLayer.arguments;
	for (i=0; i<a.length; i++) {

	//alert(layerRef+'("'+a[i]+'")'+'.style.visibility="visible"');
		if (isIE5 || isNS6) {
		eval(layerRef+'("'+a[i]+'")'+styleSwitch+'.visibility="visible"');
		}else{
		eval(layerRef+'["'+a[i]+'"]'+styleSwitch+'.visibility="visible"');
		}
	}
}


function hideLayer(){
	var a = hideLayer.arguments;
	//alert(hideLayer.arguments);
	for (i=0; i<a.length; i++) {
//alert(a[i]);
		if (isIE5 || isNS6) {
		eval(layerRef+'("'+a[i]+'")'+styleSwitch+'.visibility="hidden"');
		} else{
		eval(layerRef+'["'+a[i]+'"]'+styleSwitch+'.visibility="hidden"');
		}
	}
}