Local control semantic contracts¶

RAVET's shared controls use native form elements and explicit ARIA state for custom controls. Consumers provide visible labels, useful names, content, layout and focus styling. These runtime DOM contracts let a consumer build a labelled UI; they do not certify an OS accessibility tree or screenreader.

Custom knob disabled state¶

Knob.setEnabled(boolean) coordinates the custom slider and its optional native number. Disabling publishes aria-disabled=true, removes the knob from sequential Tab traversal and natively disables the paired number. Re-enabling restores the owned prior tabindex and the number's original disabled attribute. Initial native or ARIA-disabled state starts disabled; constructing inside a hidden panel does not permanently disable the knob. An originally disabled number remains disabled when the knob is re-enabled. Consumers own ancestor/native disabled state and explicitly refresh after stylesheet/media changes.

Disabling first ends an active parameter gesture. A refused or throwing end leaves programmatic enabled state and attributes unchanged, retains the original owner and blocks all new edits and re-enable requests until an accepted end() retry. setEnabled(false) may also retry that end. Key/pointer release and explicit end() remain recovery paths. Successful disposal ends the gesture, disconnects observation/listeners and restores original tabindex, aria-disabled and paired number disabled attributes; rejected disposal preserves the owner for retry. Transport callback reentry cannot mutate, dispose or replace that owner mid-send.

Disabled knobs reject keyboard, pointer, number, double-click and direct begin/ change/commit edits. No global focus move occurs: removing an already-focused knob from Tab order does not imply that native focus is cleared. Healthy disabled knobs remain eligible for update(value) subject to the existing focused/active-edit refresh suppression. Updates and enabling reject removed/adopted nodes or paired inputs and a closed original window. Disposal still restores already-owned attributes as cleanup, including on retired nodes.

Original-document observation detects disabled/hidden/inert/ARIA, style/class and membership changes; refresh() provides an immediate check. Unavailable live original pairs leave Tab traversal and attempt end while preserving refused ownership. A retired/adopted pair takes only the recovery path, with no new presentation writes. Consumers finish/dispose before retiring the document/window. There is no cross- origin or shadow-root traversal, automatic focus relocation or end-slot guarantee.

Before new host begin/edit messages, eligibility is checked again after existing owner end callbacks. After an accepted message, pair ownership and edit eligibility are checked again before display updates. If that callback retires the target, an accepted begin remains owned and attempts end; refusal leaves pending recovery. An accepted value/edit is already sent to the consumer host and cannot be rolled back by this local UI. The UI returns false and leaves its old display rather than painting a removed/adopted/disabled target. Consumers reconcile host acknowledgement.

Meter label and formatter ownership¶

AccessibleMeter requires one connected native meter and reading element in the same live document. Its explicit bounded label owns aria-label and removes competing aria-labelledby, which has priority in the browser's accessible name computation. Disposal restores both original name attributes exactly. Consumers supply any visible caption and meaningfully associate related text themselves.

Formatting still accepts a frozen finite reading and returns 1..4096 nonblank UTF-16 code units. Nested update() during a formatter rejects. Disposal, removal or adoption during formatting rejects before meter value, value text or visible reading mutation. The snapshot/visible text retains peak and RMS beyond the visual meter's clamped range; invalid readings/formatters preserve the display.

Evidence¶

The semantic fixture checks all twelve components' native or explicit roles, names and current states, plus disabled ownership, rejected-end recovery, post-callback retirement and exact restoration in Chromium and hidden macOS WebKit. It reads DOM/native properties; collaborative preview semantic names are automation observations, not a recorded native accessibility tree. Trusted Chromium Tab reaches the enabled knob and number, then skips the disabled pair. ArrowRight produces one begin/value/end on the enabled knob and no edit on the programmatically focused disabled knob. document.hasFocus() === false outside trusted routing remains explicit. Other platforms, actual assistive technology, native-window focus and deadline/global- memory bounds require independent evidence. See ADR0200.