function ro_Bild(no,which){
//alert(document.getElementById(no).style.backgroundColor);
	document.images[no].src="img/".concat(which);
}

function openWindow(datei, fenstername, w, h){
	var window_top = (screen.height-h)/2;
    var window_left = (screen.width-w)/2;
	fenster=open(datei,fenstername,"width="+w+ ",height=" +h+ ",dependent=" +1+ ",resizable=" +0+ ",scrollbars=" +1+ ",top=" + window_top + ",left=" + window_left);
	if (fenster) fenster.focus();
	return !fenster;

}