function changenavover(id) {
		document.getElementById(id).style.backgroundImage = "url(pics/" + id + "_a.gif)";
		document.getElementById(id+"pfeil").style.backgroundImage = "url(pics/nav_pfeil_a.gif)";
	}
	
	function changenavout(id) {
		document.getElementById(id).style.backgroundImage = "url(pics/" + id + ".gif)";
		document.getElementById(id+"pfeil").style.backgroundImage = "url(pics/nav_pfeil.gif)";
	}