function hideAllBoxes()
  {
    var alldivs = document.getElementsByTagName('div');
    for(i = 0; i < alldivs.length; i += 1)
      if(alldivs[i].id.slice(0,6) == 'popup_')
        alldivs[i].style.display = 'none';
  }
  function hideBox(boxId)
  {
    new Effect.Fade(boxId, { duration: 0.2 } );
  }