var preload = false;

ns4 = (document.layers)? true:false;
ie4 = (document.all)? true:false;
dom = (document.getElementById)? true:false;

function preloadImages() {
      if(document.images) {
            bulletOn = new Image();
            bulletOn.src = "furniture/buttons/arrow_dwn.png";
            bulletOff = new Image();
            bulletOff.src = "furniture/buttons/arrow.png";
            preload = true;
      }
}

function buttonOn(imageName) {
      if(!preload) return;
      if(document.images) {
            document.images[imageName].src = bulletOn.src;
      }
}

function buttonOff(imageName) {
      if(!preload) return;
      if(document.images) {
            document.images[imageName].src = bulletOff.src;
      }
}