if (document.images) {
  image0 = new Image;
  image1 = new Image;
  image2 = new Image;
  image0.src = 'graphics\/pic1a.gif';
  image1.src = 'graphics\/pic2a.gif';
  image2.src = 'graphics\/pic3a.gif';
} else {
  image0 = '';
  image1 = '';
  image2 = '';
  document.rollimg = '';
}
var cap = ['Picture One',
           'Second Picture',
           'Three'];

function rollover(n) {
document.rollimg.src = window['image'+n].src;
document.getElementById('caption').innerHTML = cap[n];
}