//Specify background images to slide

function cycleBan() {
 var whichImage = Math.round(Math.random()*(14));
  document.getElementById('header').style.backgroundImage="url('rotate/"+ whichImage + ".jpg')";
  // set the time below for length of image display
  // i.e., "4*1000" is 4 seconds
  setTimeout("cycleBan()", 5*1000);
}
window.onload=cycleBan;