<!--
var rotation = 0;

function swapHeaderImage() {
  var bannerImg = document.getElementById("bannerImg");
  if (bannerImg) {
    if (rotation == 0) {
      // don't switch image on first iteration
      }
    else if (rotation % 2 == 0) {
      bannerImg.src = 'images/become_member1.jpg';
      }
    else {
      bannerImg.src = 'images/become_member2.jpg';
      }
    rotation++;
    window.setTimeout("swapHeaderImage()",5000);
    }
  }

addEvent(window,'load',swapHeaderImage);
//-->