if (document.images) 
{
	img1on = new Image();
	img1on.src = "images/top_mail_icon_.gif";
	img1off = new Image();
	img1off.src = "images/top_mail_icon.gif";

	img2on = new Image();
	img2on.src = "images/top_map_icon_.gif";
	img2off = new Image();
	img2off.src = "images/top_map_icon.gif";

	img3on = new Image();
	img3on.src = "images/top_home_icon_.gif";
	img3off = new Image();
	img3off.src = "images/top_home_icon.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"); }
}