var clipTop = 0;
var clipWidth = 170;
var clipBottom = 50;
var topper = 300;
var lyrheight = 0;
var time,amount,theTime,theHeight,DHTML;

function init()
{
    DHTML = (document.getElementById || document.all || document.layers)
    if (!DHTML) return;
    var x = new getObj('example');
    if (document.layers)
    {
        lyrheight = x.style.clip.bottom;
        lyrheight += 20;
        x.style.clip.top = clipTop;
        x.style.clip.left = 0;
        x.style.clip.right = clipWidth;
        x.style.clip.bottom = clipBottom;
    }
    else if (document.getElementById || document.all)
    {
        lyrheight = x.obj.offsetHeight;
        x.style.clip = 'rect('+clipTop+'px,'+clipWidth+'px,'+clipBottom+'px,0)';
    }
}

function getObj(name)
{
  if (document.getElementById)
  {
    this.obj = document.getElementById(name);
    this.style = document.getElementById(name).style;
  }
  else if (document.all)
  {
    this.obj = document.all[name];
    this.style = document.all[name].style;
  }
  else if (document.layers)
  {
    this.obj = document.layers[name];
    this.style = document.layers[name];
  }
}

function scrollayer(layername,amt,tim)
{
    if (!DHTML) return;
    thelayer = new getObj(layername);
    if (!thelayer) return;
    amount = amt;
    theTime = tim;
    realscroll();
}

function realscroll()
{
    if (!DHTML) return;
    clipTop += amount;
    clipBottom += amount;
    topper -= amount;
    if (clipTop < 0 || clipBottom > lyrheight)
    {
        clipTop -= amount;
        clipBottom -= amount;
        topper += amount;
        return;
    }
    if (document.getElementById || document.all)
    {
        clipstring = 'rect('+clipTop+'px,'+clipWidth+'px,'+clipBottom+'px,0)';
        thelayer.style.clip = clipstring;
        thelayer.style.top = topper + 'px';
    }
    else if (document.layers)
    {
        thelayer.style.clip.top = clipTop;
        thelayer.style.clip.bottom = clipBottom;
        thelayer.style.top = topper;
    }
    time = setTimeout('realscroll()',theTime);
}

function stopScroll()
{
    if (time) clearTimeout(time);
}