function showPanel(num)
{
	var myPanel = document.getElementById("panel_" + num);
	myPanel.style.visibility = "visible";
}

function hidePanels()
{
	for (var num = 1; num <= 4; num++)
	{
		var myPanel = document.getElementById("panel_" + num);
		myPanel.style.visibility = "hidden";
	}
}