Simulate Access combo Not In List in form dropdown

[CortoMaltes]

Hi,
How is it possible to add a value to a combo dynamically, sort of reproducing the MS Access Not In List event?
I want to be able to put a button next to the input box, opening a new window where users input a value not in the dropdown list and reload the list in the form, preserving any other data already input by the user (i.e. without reloading the page)? Thanks.

 

[codestorm]

Sounds like a job for client-side JS .. bearing in mind that if the page isn't reloaded the list addition isn't saved to a database. codestorm
Fire bad. Tree pretty. - Buffy
select * from population where talent > 'average'
<insert witticism here>

 

[CortoMaltes]

I thought so but my searches didn't return anything useful (JS scripts). Would you have any reference about a good enough script? Thanks!