var state = 'none';

function showHide(layer_ref)
{
	if (state == 'block')
	{
		state = 'none';}
	else
	{
		state = 'block';}

	if (document.all)
	{
		eval( "document.all." + layer_ref + ".style.display = state");
	}

	if (document.layers)
	{
		document.layers[layer_ref].display = state;
	}

	if (document.getElementById && !document.all)
	{
		document.getElementById(layer_ref).style.display = state;
	}
}