function resolution(id) {
	if (typeof screen.width != 'undefined') {
		element = document.getElementById(id);
		if (typeof element != 'undefined') {
			element.src = '/images/resolution.php?width='+screen.width+'&height='+screen.height;
		} else {
			alert('Element mit id='+id+' nicht gefunden!');
		}
	}
}