if (document.images)   {
    nav01on = new Image(); nav01on.src = "images/homeButtonOver.jpg";
	nav02on = new Image(); nav02on.src = "images/parkButtonOver.jpg";
	nav03on = new Image(); nav03on.src = "images/thrillsButtonOver.jpg";
	nav04on = new Image(); nav04on.src = "images/headsButtonOver.jpg";
	nav05on = new Image(); nav05on.src = "images/funButtonOver.jpg";
	nav06on = new Image(); nav06on.src = "images/contactButtonOver.jpg";

    nav01off = new Image(); nav01off.src = "images/homeButton.jpg";
	nav02off = new Image(); nav02off.src = "images/parkButton.jpg";
	nav03off = new Image(); nav03off.src = "images/thrillsButton.jpg";
	nav04off = new Image(); nav04off.src = "images/headsButton.jpg";
	nav05off = new Image(); nav05off.src = "images/funButton.jpg";
	nav06off = new Image(); nav06off.src = "images/contactButton.jpg";
    }

function imgOn(imgName)
	{
    if (document.images)
    	{
        document[imgName].src = eval(imgName + "on.src");
        }
	}

function imgOff(imgName)
	{
    if (document.images)
    	{
        document[imgName].src = eval(imgName + "off.src");
        }
	}