function showLayer(layerName)
{
	
        if(document.layers)
		{
            //thisbrowser="NN4";
            document.layerName.visibilty="visible";
        }
        if(document.all)
		{
            //thisbrowser="ie"
			
            document.all[layerName].style.visibility="visible";
        }
        if(!document.all && document.getElementById)
		{
            //thisbrowser="NN6";
            document.getElementById(layerName).style.visibility="visible";

        }
}
function hideLayer(layerName)
{
        if(document.layers)
		{
            //thisbrowser="NN4";
            document.layerName.visibilty="hidden";
        }
        if(document.all)
		{
            //thisbrowser="ie"
            document.all[layerName].style.visibility="hidden";
        }
        if(!document.all && document.getElementById)
		{
            //thisbrowser="NN6";
            document.getElementById(layerName).style.visibility="hidden";

        }
}