function newImage(arg) {
	if (document.images) {
		rslt = new Image();
		rslt.src = arg;
		return rslt;
	}
}

function changeImages() {
	if (document.images && (preloadFlag == true)) {
		for (var i=0; i<changeImages.arguments.length; i+=2) {
			document[changeImages.arguments[i]].src = changeImages.arguments[i+1];
		}
	}
}

var preloadFlag = false;
function preloadImages() {
	if (document.images) {
		btn_home_over = newImage("images/btn_home-over.jpg");
		btn_boilers_over = newImage("images/btn_boilers-over.jpg");
		btn_unvented_over = newImage("images/btn_unvented-over.jpg");
		btn_pumps_over = newImage("images/btn_pumps-over.jpg");
		btn_gallery_over = newImage("images/btn_gallery-over.jpg");
		btn_contact_over = newImage("images/btn_contact-over.jpg");
		btn_links_over = newImage("images/btn_links-over.jpg");
		preloadFlag = true;
	}
}


function openWin(URL)
{
aWindow=window.open(URL,"Portfolio","toolbar=no,width=640,height=680,status=no,scrollbars=no,resize=no,menubar=no,history=no");
}