catch any outbound links

Google Analytics.js Outbound Link Tracking.js

  $('a:not([href*="' + document.domain + '"])').click(function(event){
    /* get all the info from the link */
    var anchor = $(this);
    var href = anchor.attr('href');
    /* check that the link isn't a relative link */
    var hrefLead = href.charAt(0);
    if (hrefLead != '.' && hrefLead != '#' && hrefLead != '/') {
      /* stop the browser redirecting away, we'll do it manually after the hit is registered with Google */
      event.preventDefault();
      /* strip the protocol, because it's wasted space */
      var hrefNoProtocol = href.replace(/http[s]?:\/\//, '');
      ga('send', 'pageview', {
        /* register the outgoing link as '/out/[outgoing link]' */
        'page': 'out/'+hrefNoProtocol,
        /* only when we've finished registering the link click, send the user to the link they clicked on */
        'hitCallback': function() {
          document.location = href;
        }
      });
    }
  });