var activeImage=null;
var activeTag=null;
var rotationInterval=null;
function startRotation()
{
  activeImage=1;
  activeTag=document.getElementById("logo"+activeImage);
  activeTag.style.display="block";
  var rotationInterval= window.setInterval("rotate()",6000);
}
function rotate()
{
  activeTag.style.display="none";
  activeImage=activeImage+1;
  activeTag=document.getElementById("logo"+activeImage);
  if (activeTag==null)
  {
    activeImage=1;
    activeTag=document.getElementById("logo"+activeImage);
  }
  activeTag.style.display="block";
}