re-enabling on invalid

[KonnorRogers]

Status

• Needs review

Related Issue(s)

• Fixes Don't disable button elements if form is using browser validation + invalid #220

We should still disable, but this re-enables if it detects an invalid event.

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[tcannonfodder]

(Copying my comments from when we first chatted so they don't get lost)

I thought about taking this approach as well, but it could break cases where someone has disabled the input independently. such as, a form is disabled until it is fully valid; for example: a login form that is only valid when an email & password are enabled, so the user has disabled the submit button until the form is valid.

When you test this behavior with submit inputs, it doesn’t appear to trigger the disable handler at all; so I think we’d want to mirror that behavior for the button elements as best as we can by just not running the code.

Essentially, I'm thinking about how the event doesn't trigger if a submit input is used. And I think that the submit event doesn't fire if constraint validation kicks in. If so, following that logic, I think it makes sense to not disable since we should not have reached that point.

[tcannonfodder]

I had some time this morning and updated my reproduction of this bug to show how "re-enabling on invalid" can break the behavior of forms that independently disable submit buttons. Code: practical-computer/mrujs-constraint-validation-bug-proof-of-concept@7f03da8

In the demo, I've created a simple "toggle lock" that disables specific submit buttons. In the non-remote form, the toggle-locked button remains locked, while in the remote form it is unlocked.

Demo video of "re-enabling on invalid" bug

Screen.Recording.2026-01-28.at.07.25.43.mov

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Demo video of "halt disabling if the parent form is invalid & uses constraint validation" (#220)

Screen.Recording.2026-01-28.at.07.32.33.mov