function rollOn(which) {
	if (document.images && (which != '')) {
		document.images[which].src = eval(which + "_over.src");
	}	else {
		return true;
	}
}

function rollOff(which) {
	if (document.images && (which != '')) {
		document.images[which].src = eval(which + "_off.src");
	}	else {
		return true;
	}
}