This makes it available for all form associated elements and not just
select and input elements. It also makes it more spec compliant,
especially around the form attribute.
The main thing missing is re-associating form elements with a form
attribute when the form attribute changes or an element with an ID
is inserted/removed or has its ID changed.
SPDX License Identifiers are a more compact / standardized
way of representing file license information.
See: https://spdx.dev/resources/use/#identifiers
This was done with the `ambr` search and replace tool.
ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
This fills in a bunch of the FIXMEs that was in prepare_script.
execute_script is almost finished, it's just missing the module side.
As an aside, let's not assert when inserting a script element with
innerHTML.
