Add Google Analytics to track a button press
take a look at Google Analytics Event Tracking:


  Event Tracking is a way to track user interaction with out registering
  a page view. Using Google Maps as an example site, event tracking
  would allow the user to track Zoom, Drag, and View Change events
  without contaminating the page view statistic.
  
  This module allows an interface for Google Analytics event tracking
  capabilities. It provides a hook for other modules or "glue code" and
  also has some handy drush commands.