function schalter(nr) {
	if(document.getElementById('kasten' + nr).style.display == '' || document.getElementById('kasten' + nr).style.display == 'block') {
		//alert(document.getElementById('kasten' + nr).style.display);
		document.getElementById('schalter' + nr).style.backgroundImage = "url(bilder/gxnav_zu.gif)";
		document.getElementById('kasten' + nr).style.display = "none";
		document.getElementById('kasten_zu' + nr).style.display = "block";
		document.getElementById('schalter' + nr).blur();
	}
	else {
		//alert(document.getElementById('kasten' + nr).style.display);
		document.getElementById('schalter' + nr).style.backgroundImage = "url(bilder/gxnav_auf.gif)";
		document.getElementById('kasten' + nr).style.display = "block";
		document.getElementById('kasten_zu' + nr).style.display = "none";
		document.getElementById('schalter' + nr).blur();
	}
}