function fensterOpen(url, breite, hoehe, title) {
// Errechnet Koordinaten, um das Popup zentriert zu platzieren
links = (screen.width/2)-(breite/2);
oben = (screen.height/2)-(hoehe/2);
//hier die funktion die das fenster öffnet
window.open(url,"Strommixer","height="+hoehe+",width="+breite+",status = no,toolbar = no,menubar = no,location = no,resizable = no,titlebar = no,scrollbars = yes,fullscreen = no,top ="+oben+",left ="+links);
}