[TYPO3-english] Something like eval to other field types or other ideas to auto-fill IRRE form

[Guillermo R. Oramas J.]

Hello.

I'm stuck with a problem.

I need to fill automatically some fields of an inline (IRRE) form based in
the fields of its parent form.

I probed with the eval user custom function that have the input type fields,
when I change the field that call the function with javascript I load the
values and pass them to the IRRE form fields. 

But I have two huge problems that I don't know how to face in Typo3
environment (In PHP - Javascript is relatively easy).

1. When I pass the values to the IRRE form Typo3 doesn't recognize it, so
despite the values are showing correctly, when I save the form nothing is
update in the MySQL tables. Even the required fields maintains their yellow
marks.

2. I want to use a button or other element type to call the Javascript code,
so is not nice to users to write some text in an empty field only with the
purpose of auto-fill the form.

I really appreciate any help. These issues are driving me crazy.  :-)