var innerLayer = ""
var outerLayer = ""
var scrollID = null

isIE = (navigator.appName.indexOf("Microsoft Internet Explorer") > -1)? true : false

function layerElement(layerName) {
  if(isIE) {
    return document.all.tags("div")[layerName]
  } else {
    return document.getElementById(layerName)
  }
}

function layerHeight(layerName) {
  if(isIE) {
    return document.all.tags("div")[layerName].scrollHeight
  } else {
    return document.getElementById(layerName).offsetHeight
  }
}

function layerTop(layerName) {
  if(isIE) {
    return document.all.tags("div")[layerName].style.pixelTop
  } else {
    return document.getElementById(layerName).style.top
  }
}

function setLayerTop(layerName, amount) {
  if(isIE) {
    document.all.tags("div")[layerName].style.pixelTop = amount
  } else {
    document.getElementById(layerName).style.top = amount
  }
}

function setInnerLayer(iLayer) {
  this.innerLayer = iLayer
}

function getInnerLayer() {
  return this.innerLayer
}

function setOutLayer(oLayer) {
  this.outerLayer = oLayer
}

function getOuterLayer() {
  return this.outerLayer
}

function setScrollingElements(oLayer, iLayer) {
  setInnerLayer(iLayer)
  setOutLayer(oLayer)
}

function scrollLayer(oLayer, iLayer, iterator) {
  clearTimeout(scrollID)
  setScrollingElements(oLayer, iLayer)
  moveLayer(iterator)
}

function moveLayer(num) {
  var innerheightY
  var outerheightY
  var pos
  var numA = 0

  posY = layerTop(getInnerLayer())
  innerheightY = layerHeight(getInnerLayer())
  outerheightY = layerHeight(getOuterLayer())
  if(parseInt(posY) <= 0) {
    posY = parseInt(posY)
  }

  pos = innerheightY - outerheightY

  if(((posY + num) <= 0) & ((posY + (num / 2)) >= -pos)) {
    setLayerTop(getInnerLayer(), (posY + num))
  }
  scrollID = setTimeout("moveLayer(" + num + ")", 50)
}