addListener( element ) to track clicks of specific buttons

In the drupal module there is a place for custom javascript code to enter in unique PIWIK events. I am trying to add a click event but it does not seem to work.

I have tried:
addListener( ‘button_show’ );
addListener( button_movie’ );
trackEvent(‘button_movie’, click, %article_name%);
piwiktracker.addListener( ‘button_movie’ );

Can you provide instruction on how to do this and get it to work?

button_show & button_movie are ID’s on the link.