function add_link(url, rel) {
  var link = document.getElementById(rel) || document.createElement('link');
  link.id = rel;
  link.rel = rel;
  link.href = url;
  document.body.appendChild(link);
}

function prerender_url(url) {
  console.log('prerender_url '+url);
  if (!url)
    return false;
  if (!url.indexOf('http') == 0)
    url = 'http://' + url;
  add_link(url, 'prerender');

  window.setTimeout(function() {
    console.log('loaded');
   // anchor.innerText = url;
  }, 0);
  console.log('prerendering: ' + url);
  return false;
}

function prerender_url_firefox(url) {
  console.log('prerender_url_firefox '+url);
  if (!url)
    return false;
  if (!url.indexOf('http') == 0)
    url = 'http://' + url;
  add_link(url, 'prefetch');

  window.setTimeout(function() {
    console.log('loaded');
   // anchor.href = url;
  }, 0);
  console.log('prerendering: ' + url);
  return false;
}