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) {
		comm_but_over = newImage("images/comm_but-over.gif");
		comm_but2_over = newImage("images/comm_but2-over.gif");
		infor_but_over = newImage("images/infor_but-over.gif");
		infor_but2_over = newImage("images/infor_but2-over.gif");
		dig_but_over = newImage("images/dig_but-over.gif");
		dig_but2_over = newImage("images/dig_but2-over.gif");
		semi_but_over = newImage("images/semi_but-over.gif");
		semi_but2_over = newImage("images/semi_but2-over.gif");
		preloadFlag = true;
	}
}