How the parts resume

A brumate page ships no code before someone uses it. The parts are built for that, and a few of their behaviors come from it.

Handlers run after the event

The loader catches an event, loads the code of its handler, and runs it once the browser is done with the event. So a handler cannot call preventDefault, and focus can have moved by the time it runs. prevent(handler, keys) from brumate/events is what applies during the event, before any code loads.

• A press keeps its pointer. A button takes pointer capture when a press starts, so its pointerup reaches it even when the pointer ends outside, and the press ends.
• Space is prevented by key, and Enter keeps its default. Space never scrolls the page. On Enter, a link follows and a submit button sends its form without any code, and the click that the browser sends after Enter does not press again.
• A disabled link has no href, so there is nothing for the browser to follow. It leaves the order of Tab, as in React Aria.
• A read-only box prevents its click with the wrapper, so the browser never toggles it, and a screen reader announces no change.
• Tab stops at one item of a toolbar, the one that had focus last. The other items leave the order of Tab, which is the roving tabindex of the WAI-ARIA toolbar.
• A toolbar prevents only Up and Down, so the page does not scroll. Home and End can scroll the page while they move focus.
• A handler checks where focus is before it shows a part as focused, since focus can have moved on.

The server renders first

• A field names its description before it knows that there is one. The server writes the input before it reaches the Text slot="description". When the browser is idle, the field leaves out the ID of a description that is not there.
• The last Breadcrumb is the one that you mark with isCurrent, since a part cannot read the structure of the markup that it gets.
• The default locale is en-US, not the language of the browser, which the server does not know. An I18nProvider sets it for the server and the browser alike.
• The focus ring follows :focus-visible, so no code listens to every key and pointer from the start of the page.
• Only an indeterminate box loads code, when the browser is idle, since only code can make a box indeterminate.

Without scripts

• A native element still works: a button sends its form, a link follows, a box checks, and the radios of a group move with the arrow keys.
• A form checks its fields in the browser, and posts its values by name.
• A part that needs code, such as a FileTrigger, says so on its page.