img1_on = new Image();
img1_on.src = "images/compd.gif";
img1_off = new Image();
img1_off.src = "images/compd_a.gif";

img3_on = new Image();
img3_on.src = "images/tepld.gif";
img3_off = new Image();
img3_off.src = "images/tepld_a.gif";
img4_on = new Image();
img4_on.src = "images/derevd.gif";
img4_off = new Image();
img4_off.src = "images/derevd_a.gif";

img5_on = new Image();
img5_on.src = "images/prj.gif";
img5_off = new Image();
img5_off.src = "images/prj_a.gif";

img6_on = new Image();
img6_on.src = "images/contd.gif";
img6_off = new Image();
img6_off.src = "images/contd_a.gif";

function rollon(imgName) 
{
	document[imgName].src = eval(imgName + "_on.src");
}
function rolloff(imgName) 
{
	document[imgName].src = eval(imgName + "_off.src");
}

var selectedElement = null;

function ShowMenu(id)
{
if (selectedElement!=null)
	{
    var curMenu = document.getElementById("Menu"+selectedElement);
    curMenu.style.visibility = "hidden";
	rollon("img" + selectedElement);
	}

if (id!=null)
	{
	var curMenu = document.getElementById("Menu"+id);
	selectedElement = id;
	curMenu.style.visibility = "visible";
	rolloff("img" + id);
	}
}