var divHeight = 215;
function preloadImages() {
  document.aImages = new Array();
  if(document.images) {
    for(var i = 0; i < preloadImages.arguments.length; i++) {
      document.aImages[i] = new Image();
      document.aImages[i].src = preloadImages.arguments[i];
    }
  }
}
preloadImages('images/btn_up_a.jpg','images/btn_up.jpg','images/btn_down_a.jpg','images/btn_down.jpg');
var scrollDivHeight;
var scrollDivTimer;
function setButtons() {
  if (document.getElementById('content').scrollTop > 0) {
    document.getElementById('btn_up').src = "images/btn_up_a.jpg";
    document.getElementById('btn_up').style.cursor = "pointer";
  }
  else {
    document.getElementById('btn_up').src = "images/btn_up.jpg";
    document.getElementById('btn_up').style.cursor = "auto";
  }
  scrollDivHeight = document.getElementById('content').scrollHeight - divHeight;
  if (document.getElementById('content').scrollTop < scrollDivHeight) {
    document.getElementById('btn_down').src = "images/btn_down_a.jpg";
    document.getElementById('btn_down').style.cursor = "pointer";
  }
  else {
    document.getElementById('btn_down').src = "images/btn_down.jpg";
    document.getElementById('btn_down').style.cursor = "auto";
  }
}
function scrollDivUp() {
  scrollDivTimer = setInterval("scrollDivUpButton()", 10);
}
function scrollDivDown() {
  scrollDivTimer = setInterval("scrollDivDownButton()", 10);
}
function scrollDivUpButton() {
  document.getElementById('content').scrollTop -= 3;
  setButtons();
}
function scrollDivDownButton() {
  document.getElementById('content').scrollTop += 3;
  setButtons();
}
function scrollDivUpMousewheel() {
  document.getElementById('content').scrollTop -= 15;
  setButtons();
}
function scrollDivDownMousewheel() {
  document.getElementById('content').scrollTop += 15;
  setButtons();
}
function clearDivTimer() {
  clearInterval(scrollDivTimer);
}
function wheel(event) {
  var delta = 0;
  if (!event) {
    event = window.event;
  }
  if (event.wheelDelta) {
    delta = event.wheelDelta/120;
    if (window.opera) {
      delta = -delta;
    }
  }
  else if (event.detail) {
    delta = -event.detail/3;
  }
  if (delta) {
    if (delta < 0) {
      scrollDivDownMousewheel();
    }
    else {
      scrollDivUpMousewheel();
    }
  }
}
if (window.addEventListener) { window.addEventListener('DOMMouseScroll', wheel, false); }
window.onmousewheel = document.onmousewheel = wheel;