function addRollovers()
{
  var links = document.getElementsByTagName('a');
  var rollover = new Image();
  for (i=0; i<links.length; i++)
  {
    if (links[i].className == "rollover")
    {
      originalSource = links[i].getElementsByTagName('img')[0].src.toString();
      stepOne = originalSource.lastIndexOf('/');
      stepTwo = originalSource.substring(stepOne+1,originalSource.length);
      newSource = "over-" + stepTwo;
      originalDirectory = originalSource.substring(0,stepOne)

      rollover.src = originalDirectory + newSource;
      links[i].onmouseover = tweenOn;
      links[i].onmouseout = tweenOff;
    }
  }
}

function tweenOn()
{
  originalSource = this.getElementsByTagName('img')[0].src.toString();
  stepOne = originalSource.lastIndexOf('/');
  stepTwo = originalSource.substring(stepOne+1,originalSource.length);
  newSource = "over-" + stepTwo;
  originalDirectory = originalSource.substring(0,stepOne+1);
  newPath = originalDirectory + newSource;
  this.getElementsByTagName('img')[0].src = newPath;
}
function tweenOff()
{
  this.getElementsByTagName('img')[0].src = originalSource;
  return;
}

var originalSource,stepOne,stepTwo,newSource,originalDirectory,newPath,testing;
window.onload = addRollovers;