There are several options:
1. Create a custom parameter in the form and pass the value in on the URL. For example create a param named p_myparam. In a WHEN-NEW-FORM-INSTANCE trigger assign the param value to the item of choice. To pass the value in from the URL, the URL would look something like this:
2. If you are using Forms 11+, you can use Java Script, but only after the form has been completed started. Refer to the documentation for more details.
Thanks for your reply
I am studying that document and has a confusion regarding following lines
To get the value of the outside field and assign it to the inside field, you could write the following PL/SQL code: