var ie4 = (document.all) ? true : false;
var ns4 = (document.layers) ? true : false;
var ns6 = (document.getElementById && !document.all) ? true : false;

function hideLayer(lay)
{
	if (ie4) {document.all[lay].style.visibility = "hidden";}
	if (ns4) {document.layers[lay].visibility = "hide";}
	if (ns6) {document.getElementById([lay]).style.display = "none";}
}

function showLayer(lay)
{
	if (ie4) {document.all[lay].style.visibility = "visible";}
	if (ns4) {document.layers[lay].visibility = "show";}
	if (ns6) {document.getElementById([lay]).style.display = "block";}
}

function writeToLayer(lay, txt)
{
	if (ie4)
	{
		document.all[lay].innerHTML = txt;
	}

	if (ns4)
	{
		document[lay].document.write(txt);
		document[lay].document.close();
	}

	if (ns6)
	{
		over = document.getElementById([lay]);
		range = document.createRange();
		range.setStartBefore(over);
		domfrag = range.createContextualFragment(txt);

		while (over.hasChildNodes())
		{
			over.removeChild(over.lastChild);
		}
		
		over.appendChild(domfrag);
	}
}