Is there any way to add custom JavaScipt functions to the UI?  Would this require a new theme?  Would it be possible to hook in my own JS file to the "minifier" to accomplish this?

I have two use cases in mind:
  1. An agent sets a ticket to a status like "waiting for vendor".  I would then like to require that the free text field for vendor reference IDs has a value.
  2. Some agents would prefer to input time with "tokens", like "1:30" for 1.5 hours, or 5m for five minutes.  A JS function could handle these translations.
Any ideas?

Hugh