function modifyLink(link) {
  inner = link.innerHTML;
  link.href = baseUrl + 'linkCheck.php?l=' + urlEncode(link.href);
  link.innerHTML = inner;
}

function changeLinks() {
  for (var i=0; i < document.links.length; i++) {
    link = document.links[i];
    if(link.hostname != location.hostname && link.protocol == 'http:') { // only modify external links
      modifyLink(link);
    }
  }
}