Open all the external and PDF links in a new window, with exceptions.

external_links.js

$(document).ready(function() {
  // Open external links in a new window, except AddThis
  $("a[href^='http']")
    .not("[href^=#]")
    .not("[href^=mailto]")
    .not("href*=example.com")
    .not("href*=addthis.com")
    .addClass("link-external")
    .attr('target', '_blank');

  // Open PDF links in a new window, 
  $("a[href$='.pdf']").addClass("link-pdf").attr('target', '_blank');
});