function toggleDyn() {
      
  if ($("dyn-groot").style.opacity == 1) {
       
    veranderOpacity("dyn-groot", false)
    //veranderOpacity("dyn", true)
  
  } else {
  
    veranderOpacity("dyn-groot", true)
    //veranderOpacity("dyn", false)
  }
  
}

function veranderOpacity(id, show) {
  
  var myFx = new Fx.Style(id, 'opacity', {duration:200}) 
  
  if (show) {
    var myFx2 = new Fx.Style(id, 'opacity').set(0);
    $(id).style.display = "block"
    myFx.custom(0,1);   
  } else {
    myFx.custom(1,0);   
  }

}