function hn_imageswap(image_id,prefix) {
	var hn_img = document.getElementById(image_id);
	if(hn_img.src.indexOf('_off')>=0) {
		hn_img.src = 'images/hauptnavigation/' + prefix + '_hover.jpg';	
	}
	else {
		if(hn_img.src.indexOf('_hover')>=0) {
			hn_img.src = 'images/hauptnavigation/' + prefix + '_off.jpg';	
		}
	}
}

function tn_imageswap(image_id) {
	var tn_img = document.getElementById(image_id);
	if(tn_img.src.indexOf('mode=off')>=0) {
			var tmp_src = tn_img.src.replace(/mode=off/,"mode=hover");
			tn_img.src = tmp_src;
	}
	else {
		if(tn_img.src.indexOf('mode=hover')>=0) {
			var tmp_src = tn_img.src.replace(/mode=hover/,"mode=off"); 
			tn_img.src = tmp_src;
		}
	}
}