// show an element
//changeObjectVisibility('myObjectId', 'visible');
// hide an element
//changeObjectVisibility('myObjectId', 'hidden');
function changeObjectVisibility(objectId, newVisibility) {
	var styleObject = getStyleObject(objectId, document);
    if(styleObject) {
	styleObject.visibility = newVisibility;
	return true;
    } else {
	return false;
    }
} 
function getStyleObject(objectId) {
	if(document.getElementById && document.getElementById(objectId)) {
		return document.getElementById(objectId).style;
	} else if (document.all && document.all(objectId)) {
		return document.all(objectId).style;
	} else if (document.layers && document.layers[objectId]) {
		return getObjNN4(document,objectId);
	} else {
		return false;
	}
} 
function getObjNN4(obj,name)
{
	var x = obj.layers;
	var foundLayer;
	for (var i=0;i<x.length;i++)
	{
		if (x[i].id == name)
		 	foundLayer = x[i];
		else if (x[i].layers.length)
			var tmp = getObjNN4(x[i],name);
		if (tmp) foundLayer = tmp;
	}
	return foundLayer;
}