How to Modify a DoubleClick Advertisement

index.js

$(document).ready(function() {
  /*
  *  ... 
  *  Load in DFP Loading Code, the important thing here is that we 
  *  are adding in tht `slotRenderEnded` Event Listener. When triggered, 
  *  it will fire the slotRenderedEventMethod function listed below.
  */
  googletag
    .pubads()
    .addEventListener('slotRenderEnded', slotRenderedEventMethod)
  ; // close googletag
}); // close $(document).ready

var slotRenderedEventMethod = function(event) {
  if (event.isEmpty === false) {
    var _thisAdvertisement = $('#' + event.slot.getSlotElementId());
    
    /*
    *  DFP will load in multiple iframes into the block, dont access
    *  the __hidden__ one.  Its possible for DFP to return multiple 
    *  content iFrames, this accounts for that.
    */
    _thisAdvertisement.find('iframe:not([id$="__hidden__"])').each(function() {
      var _thisIFrame = $(this);
      
      // Set a New Width for the iFrame
      _thisIFrame.prop('width', '100%');
      
      /*
      *  Its possible for DFP to return multiple Anchor Tags in the 
      *  iFrame, this accounts for that possiblity.
      */
      _thisIFrame.contents().find('a').each(function() {
        var _thisAnchor = $(this);
        var _thisURL = _thisAnchor.attr('href');
        
        console.log("Click URL: " + _thisURL);
        /*
        *  Now we have the URL, we can perform whatever actions 
        *  We wanted to do.
        */
      }); // close _thisIFrame..find("a")
      
    }); // close _thisAdvertisement.find('iframe').each()
  } else {
    // Send a notice into console that no advertisement was found
    console.warn('No advertisements for ' + event.slot.getSlotElementId());
  } // close if (event.isEmpty)
}; // close slotRenderedEventMethod