function rollover1(imgName, obj)
{
  var reg=/img\s+src=\"([^\"]*)\"/;
  var what_should_be="img src=\""+imgName+"\"";
  obj.innerHTML=obj.innerHTML.replace(reg, what_should_be);
}
function rollover(imgName, obj)
{
  var img_id="img_"+obj.id;
  img_handle=document.getElementById(img_id);
  img_handle.src=imgName;
}