function imageSwap(imagename, imagesrc)
{
  var objStr,obj;
  if(document.images)
   {
    if (typeof(imagename) == 'string')
	{
      objStr = 'document.' + imagename;
      obj = eval(objStr);
      obj.src = imagesrc;
    }
    else if ((typeof(imagename) == 'object') && imagename && imagename.src)
    {
      imagename.src = imagesrc;
    }
  }
}