function externalLinks()
{
  if (!document.getElementsByTagName) {
    return
  }
  var anchor
  var anchors = document.getElementsByTagName('a')
  for (var i = 0; i < anchors.length; i++) {
    anchor = anchors[i]
    if (anchor.getAttribute('href') && anchor.getAttribute('rel') == 'external') {
      anchor.target = '_blank'
    }
  }
}