DOM gaps

Bindings that used to be declared in the IDL and do nothing — so 'x' in obj was true and obj.x was undefined.

running…

Automatic

checkexpectedgot

Manual

1. Wheel events

Scroll the wheel over the dashed box. Nothing used to fire a wheel event at all, and the deltas read undefined.

scroll here
no wheel event yet

2. Keyboard legacy codes

Type into the field — letters, Enter, arrows, punctuation.

no keydown yet

3. Focus and activeElement

4. Text selection

5. <details> and <dialog>

a disclosureits content

a dialog

6. Pointer handler attributes

addEventListener('pointerdown') already worked; el.onpointerdown = fn dropped the function.