if (document.images)
{            
	img1on = new Image();	img1on.src = "images/navi_home_on.gif";
	img2on = new Image();	img2on.src = "images/navi_products_on.gif";
	img3on = new Image();	img3on.src = "images/navi_aboutus_on.gif";
	img4on = new Image();	img4on.src = "images/navi_contact_on.gif";

	img1off = new Image();	img1off.src = "images/navi_home.gif";
	img2off = new Image();	img2off.src = "images/navi_products.gif";
	img3off = new Image();	img3off.src = "images/navi_aboutus.gif";
	img4off = new Image();	img4off.src = "images/navi_contact.gif";
}

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");
	}
}