var preloadFlag = false;   // Hat Preload geklappt?

// Beim Klick auf das Menue das Submenue- und Mainframe laden
function menuClick(uriMenu, uriMain) {
  parent.submenuframe.location.href = uriMenu;
  parent.mainframe.location.href = uriMain;
}

// Speicher reservieren und Bild laden
function newImage(arg) {
  if (document.images) {
    rslt = new Image();
    rslt.src = arg;
    return rslt;
  }
}

// Alle Buttons zurücksetzen. Keine LED leuchtet mehr.
function resetButtons() {
  document['btn1'].src = 'images/btn.gif';
  document['btn2'].src = 'images/btn.gif';
  document['btn3'].src = 'images/btn.gif';
  document['btn4'].src = 'images/btn.gif';
  document['btn5'].src = 'images/btn.gif';
  document['btn6'].src = 'images/btn.gif';
}

// Bilder Wechseln. Immer Parameterpaar übergeben: Zielbild & Datei!
function changeImages() {
  if (document.images && (preloadFlag == true)) {
    for (var i=0; i<changeImages.arguments.length; i+=2) {
      document[changeImages.arguments[i]].src = changeImages.arguments[i+1];
    }
  }
}

// Bilder-Preload
function preloadImages() {
  if (document.images) {
    bigdisplayleft_btn1_click = newImage("images/bigdisplayleft-btn1_click.gif");
    bigdisplayleft_btn2_click = newImage("images/bigdisplayleft-btn2_click.gif");
    bigdisplayleft_btn3_click = newImage("images/bigdisplayleft-btn3_click.gif");
    bigdisplayleft_btn4_click = newImage("images/bigdisplayleft-btn4_click.gif");
    bigdisplayleft_btn5_click = newImage("images/bigdisplayleft-btn5_click.gif");
    bigdisplayleft_btn5_click = newImage("images/bigdisplayleft-btn6_click.gif");
    bigdisplayright_face = newImage("images/bigdisplayright_face.gif");
    bigdisplayright_x = newImage("images/bigdisplayright_x.gif");
    lcd_btn1_over = newImage("images/lcd-btn1_over.gif");
    lcd_btn2_over = newImage("images/lcd-btn2_over.gif");
    lcd_btn3_over = newImage("images/lcd-btn3_over.gif");
    lcd_btn4_over = newImage("images/lcd-btn4_over.gif");
    lcd_btn5_over = newImage("images/lcd-btn5_over.gif");
    lcd_btn6_over = newImage("images/lcd-btn6_over.gif");
    mailtonsb_over = newImage("images/mailtonsb-over.gif");
    gotonsbnet_over = newImage("images/gotonsbnet-over.gif");
    preloadFlag = true;
  }
}