var DHTML = (document.getElementById || document.all || document.layers);
function getObj(name)	{
	if (document.getElementById)	{    	// DOM level 1 browsers: IE 5+, NN 6+
	this.obj = document.getElementById(name);
	this.style = document.getElementById(name).style;
	}
	else if (document.all)	{  			// IE 4
	this.obj = document.all[name];
	this.style = document.all[name].style;
	}
	else if (document.layers)  { 			// NN 4
		this.obj = document.layers[name];
		this.style = document.layers[name];
	}
}
// this function makes a Layer visible
function showLayer(visiblechunk) {
	if (!DHTML) return;	
	var visLayer = new getObj(visiblechunk);
	visLayer.style.display = 'block';
}

// this function makes a layer invisible	
function hideLayer(invisiblechunk) {
	if (!DHTML) return;
	var hiddenLayer = new getObj(invisiblechunk);
	hiddenLayer.style.display = 'none';
}