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');
	}
}

nav_contacton = new Image(); 
nav_contacton.src = "images/nav_contact_on.gif";
nav_contactoff = new Image(); 
nav_contactoff.src = "images/nav_contact.gif";

nav_galleryon = new Image(); 
nav_galleryon.src = "images/nav_gallery_on.gif";
nav_galleryoff = new Image(); 
nav_galleryoff.src = "images/nav_gallery.gif";

nav_homeon = new Image(); 
nav_homeon.src = "images/nav_home_on.gif";
nav_homeoff = new Image(); 
nav_homeoff.src = "images/nav_home.gif";

nav_newson = new Image(); 
nav_newson.src = "images/nav_news_on.gif";
nav_newsoff = new Image(); 
nav_newsoff.src = "images/nav_news.gif";

nav_presson = new Image(); 
nav_presson.src = "images/nav_press_on.gif";
nav_pressoff = new Image(); 
nav_pressoff.src = "images/nav_press.gif";