function openWindow(theURL, winName, winWidth, winHeight, otherFeatures) {
    var x = 0;
    var y = 0;
    x = (screen.availWidth - 12 - winWidth) / 2;
    y = (screen.availHeight - 48 - winHeight) / 2;
    if (otherFeatures != "") { otherFeatures = "," + otherFeatures }
    var features = "screenX=" + x + ",screenY=" + y + ",width=" + winWidth +
        ",height=" + winHeight + ",top=" + y + ",left=" + x + "'" + otherFeatures;
    newwindow = window.open(theURL, winName, features);
    if (window.focus) { newwindow.focus() }
    if (window.confirm) {
        //alert('ok');
    }
    return newwindow;

}

function test() {
    alert('test');
}

function showFoto(bestand) {
    openWindow(bestand, 'bartels_foto', '1000px', '800px', '');
}