Function event_key 

pub fn event_key() -> String

eventKey() -> Text — the key of the keyboard event being dispatched, "" otherwise.

★ THE ONE THING A KEY MODIFIER NEEDS. on-keydown.enter gates on which key was pressed, and no accessor reported one — eventValue is the input’s VALUE, which for a keydown is the text so far, not the keystroke. So the browser tier registered a listener with no key comparison while the reference tier gated correctly, and the modifier was refused rather than guessed.