Update Resources/public/js/select.js

Added a change trigger when updating the output field.
Can be useful if you would like to use the field in javascript. 

In my case I want to watch the field for changes, to generate a route based on the title and the parent node and set that in a custom field.
Merge pull request #26 from wjzijderveld/patch-1

Update Resources/public/js/select.js