<!--


var layerRef = "";		//  id vd layer die zichtbaar wordt
var layerRefOld = "panel1";	//  id vd layer die zichtbaar is
var layRef = "";		//  schakel variabele


function changeState (layerRef)
	{
	var blockElement = document.getElementById(layerRefOld);
	var state = blockElement.style.visibility;
	if (state == "visible") {
		blockElement.style.visibility = "hidden";
		if (layerRef != layerRefOld) {
			toggleVis (layerRef);
			}
		} else {
		if (layerRef == layerRefOld) {
			blockElement.style.visibility = "visible";
			} else {
			toggleVis (layerRef);
			}
		}
	layerRefOld = layerRef;

	}

function toggleVis (layRef)
	{
	var blockElement = document.getElementById(layRef);
	var state = blockElement.style.visibility;
	if (state == "visible") {
		blockElement.style.visibility = "hidden";
		} else {	
		blockElement.style.visibility = "visible";
		}
	}

-->