Uncaught TypeError: Cannot set property 'bootstrap' of undefined
Drupal exports in javascript the Drupal variable that has several subitems inside depending on your configuration. Your error suggest that the bootsrap property does not exist (at least yet). You can easily make sure that this is the case by opening the console in your browser (f12 in chrome) and type: console.log(Drupal.behaviors); if the property is not there you cannot use it. 

Make sure you re loading the bootstrap library correctly. Usually you can do this by downloading the bootstrap module/theme or by using the libraries module.

Also note that Drupal behaviors intend to run every time an 'ajax' call is made by in a drupal page. I m putting ajax in quotes because drupal actually uses a legacy way for ajax called AHAH