function doImage(url,breit,hoch) {
links= (screen.width - breit) / 2;
oben= (screen.height - hoch) / 2;
var attr = "left=" + links + " ,top=" + oben + " ,width="+breit+" ,height="+hoch + " ,resizable=yes";
ansicht = window.open(url,"Bildauswahl",attr);
ansicht.document.write('Test
');
}