var duration = 1000; 
var steps = 20; 
var delay = 5000; 

function fadeIn()
{  
  for (i = 0; i <= 1; i += (1 / steps)) 
  {
    setTimeout("setOpacity(" + i + ")", i * duration);
  }
  //setTimeout("fadeOut()", delay);
}

function fadeOut() 
{
  for (i = 0; i <= 1; i += (1 / steps)) {
    setTimeout("setOpacity(" + (1 - i) + ")", i * duration);
  }
  setTimeout("fadeIn()", duration);
}

function setOpacity(level) 
{
  var element = document.getElementById('dyna');
  element.style.opacity = level;
  element.style.MozOpacity = level;
  element.style.KhtmlOpacity = level;
  element.style.filter = "alpha(opacity=" + (level * 100) + ");";
}