function ajax_a () {
	$('a').style.backgroundImage="url(http://www.pc-fuer-trier.de/lobo/images/navi/aktive.png)";
	$('b').style.backgroundImage="none";
	$('c').style.backgroundImage="none";
	$('d').style.backgroundImage="none";
	$('e').style.backgroundImage="none";
	$('f').style.backgroundImage="none";
}

function ajax_b () {
	$('a').style.backgroundImage="none";
	$('b').style.backgroundImage="url(http://www.pc-fuer-trier.de/lobo/images/navi/aktive.png)";
	$('c').style.backgroundImage="none";
	$('d').style.backgroundImage="none";
	$('e').style.backgroundImage="none";
	$('f').style.backgroundImage="none";
}

function ajax_c () {
	$('a').style.backgroundImage="none";
	$('b').style.backgroundImage="none";
	$('c').style.backgroundImage="url(http://www.pc-fuer-trier.de/lobo/images/navi/aktive.png)";
	$('d').style.backgroundImage="none";
	$('e').style.backgroundImage="none";
	$('f').style.backgroundImage="none";
}

function ajax_d () {
	$('a').style.backgroundImage="none";
	$('b').style.backgroundImage="none";
	$('c').style.backgroundImage="none";
	$('d').style.backgroundImage="url(http://www.pc-fuer-trier.de/lobo/images/navi/aktive.png)";
	$('e').style.backgroundImage="none";
	$('f').style.backgroundImage="none";
}

function ajax_e () {
	$('a').style.backgroundImage="none";
	$('b').style.backgroundImage="none";
	$('c').style.backgroundImage="none";
	$('d').style.backgroundImage="none";
	$('e').style.backgroundImage="url(http://www.pc-fuer-trier.de/lobo/images/navi/aktive.png)";
	$('f').style.backgroundImage="none";
	window.open('kontakt_php.php','displayWindow', 'width=510,height=600');
}

function ajax_f () {
	$('a').style.backgroundImage="none";
	$('b').style.backgroundImage="none";
	$('c').style.backgroundImage="none";
	$('d').style.backgroundImage="none";
	$('e').style.backgroundImage="none";
	$('f').style.backgroundImage="url(http://www.pc-fuer-trier.de/lobo/images/navi/aktive.png)";
}