function $(elemId)
{
  return document.getElementById(elemId);
}

sfHover = function()
{
  var sfElems = $('image_container').getElementsByTagName('img');
  
  for (var i = 0; i < sfElems.length; i++)
  {
    sfElems[i].onmouseover = function()
    {
      this.className += ' sfhover';
    };
    
    sfElems[i].onmouseout = function()
    {
      this.className = this.className.replace(new RegExp(' sfhover\\b'), '');
    };
  }
}

if (window.attachEvent)
  window.attachEvent('onload', sfHover);