How to track multiple links and add link-specific properties for the event by using a callback method.

trackLink.js

// Grab a bunch of links.
var $links = $('.free-trial-links');

// Call `trackLink` with your links, and a callback function instead 
// of a normal `properties` object. The function will receive the 
// link element that was clicked as it's first argument.
analytics.trackLink($links, 'Clicked Free-Trial Link', function (link) {
  return {
    href : $(link).attr('href'),
    name : $(link).text()
  }
});