var varSpeed = 3;
var scrollObj = document.getElementById? document.getElementById("content") : document.all.content;
var contentHeight = scrollObj.offsetHeight;

function scrollDown() {
  if (parseInt(scrollObj.style.top) >= (contentHeight*(-1)+197)) {
    scrollObj.style.top = parseInt(scrollObj.style.top) - varSpeed + "px";
  }
  varScrollDown = setTimeout("scrollDown()",20);
}

function scrollUp() {

  if (parseInt(scrollObj.style.top) < 0) {
    scrollObj.style.top = parseInt(scrollObj.style.top) + varSpeed + "px";
  }
  varScrollUp = setTimeout("scrollUp()",20);
}

function getContentHeight(){
    contentHeight = scrollObj.offsetHeight;
}