function stripe(elementId) {
	var element = $(elementId);
	if (!element) { return; }
	var canBeStriped = {'ul':'li', 'ol':'li', 'table':'tr'};
	var elementsToStripe = []
	for (tagName in canBeStriped) {
		tmp = element.getElementsByTagName(tagName);
		applyStripes(tmp, tagName);
	}
	function applyStripes(e, node) {
		var objectsToStripe; // will contain <li>s or <td>s
		for (var i = 0; i < e.length; i++) {
			objectsToStripe = e[i].getElementsByTagName(canBeStriped[node]);
			for (var j = 0; j < objectsToStripe.length; j++) {
				if ( j % 2 == 0) { //if index/2 has no remaineder, element is even-numbered
						Element.addClassName(objectsToStripe[j], 'even');
				}
			}
		}
	}
}