var timer;
var current = 0;
var delay = 5;
var fade;

var viewports = new Array(7,4,8,9);

function initRotate(){
  fade = (document.getElementById('rotate').filters && document.getElementById('rotate').filters.length>0);
  timer = setTimeout('rotateImage()',delay*1000)
}

function rotateImage(){
  if (fade) { document.getElementById('rotate').filters[0].Apply(); }
  document.getElementById('rotate').src = '_images/viewport-'+viewports[current]+'.jpg';
  if (fade) { document.getElementById('rotate').filters[0].Play(); }
  pause = delay*1000;
  if (fade) { pause += 3; }
  timer = setTimeout('rotateImage()',pause)
  current++;
  if (current >= viewports.length) { current = 0; }
}