Dynamic search of custom field (select box)

I have installed version 4.2.10.
I imported and updated the older version’s (3.8.4) RT database.
So far all seems to be working fine.

I have a custom field on my Ticket/Create.html page (Customers) which is a
’Select one value’ Select box, that is loaded using a package
(RT::CustomFieldValues::Customers) located in
rt4/local/lib/RT/CustomFieldValues and contains a very large number of

I have added a text box above this select box (named ‘Search Customers’) and

would like to modify the contents of the select box each time the "keyup"
event is fired for this text box; and base the query which loads the select
box with a where clause similar to "where customer_name like ‘%%’.

I have searched the online documentation, googled this to death, am usually
pretty good at sniffing out potential solutions on the web but this is
eluding me.

I just can’t find out what I need to do to:

  1. reload the Ticket/Create page on the ‘Select Customers’ keyup event;
  2. pass the text box content (value) to the query in

Any assistance with this would be greatly appreciated.