function externalLinks() {
  var popupRE = /external\[(\d+),(\d+)\]/gi;
  var links = $('a[rel^="external"]');
  var rel, width, height;
  
  links.click(function() {
    rel = $(this).attr('rel');
    if(rel == "external") {
      window.open($(this).attr('href'));
      return false;
    } else if(rel.match(popupRE)) {
      width = RegExp.$1;
      height = RegExp.$2;
      window.open($(this).attr('href'), '', 'width=' + width + ',height=' + height + ',scrollbars=yes');
      return false;
    }
  });
}