if (document.images) {
// create all global variables for image preloading.
	var imgNewsOn = new Image(64, 40); 
	var imgNewsOff = new Image(64, 40); 
	var imgStyleOn = new Image(72, 40); 
	var imgStyleOff = new Image(72, 40); 
	var imgPlayOn = new Image(66, 40); 
	var imgPlayOff = new Image(66, 40); 
	var imgTravelOn = new Image(87, 40); 
	var imgTravelOff = new Image(87, 40); 
	var imgNatureOn = new Image(93, 40); 
	var imgNatureOff = new Image(93, 40); 
	var imgCreateOn = new Image(82, 40); 
	var imgCreateOff = new Image(82, 40); 
}

function preloadImages(relRoot) {
// this function preloads all images used in the top navigation
	if (imgNewsOn) {
		imgNewsOn.src = "images/nav_news_on.gif";
	}
	if (imgNewsOff) {
		imgNewsOff.src = "images/nav_news_off.gif";
	}
	if (imgStyleOn) {
		imgStyleOn.src = "images/nav_style_on.gif";
	}
	if (imgStyleOff) {
		imgStyleOff.src = "images/nav_style_off.gif";
	}
	if (imgPlayOn) {
		imgPlayOn.src = "images/nav_play_on.gif";
	}
	if (imgPlayOff) {
		imgPlayOff.src = "images/nav_play_off.gif";
	}
	if (imgTravelOn) {
		imgTravelOn.src = "images/nav_travel_on.gif";
	}
	if (imgTravelOff) {
		imgTravelOff.src = "images/nav_travel_off.gif";
	}
	if (imgNatureOn) {
		imgNatureOn.src = "images/nav_nature_on.gif";
	}
	if (imgNatureOff) {
		imgNatureOff.src = "images/nav_nature_off.gif";
	}
	if (imgCreateOn) {
		imgCreateOn.src = "images/nav_create_on.gif";
	}
	if (imgCreateOff) {
		imgCreateOff.src = "images/nav_create_off.gif";
	}

}

function swapImage(strElement, objImage) 
{	// this function swaps the image identified by strElement for a new one 
	// preloaded as objImage

	// check if the objects exists to prevent errors
	if (document.images && objImage && objImage.src && objImage.src != "") 
	{
		if (document.images[strElement]) 
		{
			document.images[strElement].src = objImage.src
		}
	}
}

function pop(path) {
	popWindow = window.open(path,'pop','width=580,height=340,toolbar=1,location=0,directories=0,status=0,menubar=1,scrollbars=1,resizable=1');
}