var prevObjectID = null;
var prevLayer = 0;			

function setLayer(objectID,layerNum) {
	var object = document.getElementById(objectID);
	object.style.zIndex = layerNum;
}

function findLayer(objectID) {
	var object = document.getElementById(objectID);
	if (object.style.zIndex != null)
		return object.style.zIndex;
	return (null);
}

function swapLayer(objectID) {
	if (prevObjectID != null) setLayer(prevObjectID,prevLayer);
	prevLayer = findLayer(objectID);
 	prevObjectID = objectID;
 	setLayer(objectID,1000);
}