Jquery.on method returns undefined is not a function
depending on the version of Drupal you are running, it is likely a jquery version issue. Drupal 7 for example defaults with jQuery 1.4 if memory serves, and .on() was added to jQuery in version 1.7.

You could try jQuery Update module:


Upgrades the version of jQuery in Drupal core to a newer version of jQuery.

Drupal 5 to jQuery 1.2.6

Drupal 6 to jQuery 1.3.2

Drupal 7 to jQuery 1.5.x, 1.7.x, 1.8.x, 1.9.x, 1.10.x and jQuery UI 1.10.2

Drupal 8: TBD