var timerID = 0;
  var tStart  = null;
  var blend = 1;

  function opacity(id, opacStart, opacEnd, millisec)
  {
    //speed for each frame
    var speed = Math.round(millisec / 100);
    var timer = 0;
    var object = document.getElementById(id).style;

    //determine the direction for the blending, if start and end are the same nothing happens
    if(opacStart > opacEnd)
    {
      object.display = (object.display == 'block') ? 'none' : 'block';

      for(i = opacStart; i >= opacEnd; i--)
      {
        setTimeout("changeOpac(" + i + ",'" + id + "')",(timer * speed));
        timer++;
      }
    }
    else if(opacStart < opacEnd)
    {
      for(i = opacStart; i <= opacEnd; i++)
      {
        setTimeout("changeOpac(" + i + ",'" + id + "')",(timer * speed));
        timer++;
      }
      object.display = (object.display == 'block') ? 'none' : 'block';
    }
  }

  //change the opacity for different browsers
  function changeOpac(opacity, id)
  {
    var object = document.getElementById(id).style;
    object.opacity = (opacity / 100);
    object.MozOpacity = (opacity / 100);
    object.KhtmlOpacity = (opacity / 100);
    object.filter = "alpha(opacity=" + opacity + ")";
  }

  function shiftOpacity(id, millisec)
  {
    //if an element is invisible, make it visible, else make it ivisible
    if(document.getElementById(id).style.opacity == 0)
    {
      opacity(id, 0, 100, millisec);
    }
    else
    {
      opacity(id, 100, 0, millisec);
    }
  }

  function anzeigen(Obj)
  {
    if (document.getElementById(Obj).style.display=='none')
      document.getElementById(Obj).style.display='block';
    else
      document.getElementById(Obj).style.display='none';
  }