Test if form is loaded in "on add"-, "on edit"-, or "on delete"-mode?

Test if form is loaded in "on add"-, "on edit"-, or "on delete"-mode?

Hi!

I have an "on user input" field action for a dropdown field that I only want executed if the form is loaded in "On Add"-mode.

Can I somehow test for this in an if-statement in the script?

Thanks,

Espen