accessibility - Is there any documentation on how screen readers should act? -

i'm reviewing , recommending changes/fixes small web application enhanced more accessible.

the problem keep running there doesn't seem details how screen readers should (or do) work.

for instance, if @ accessible rich internet applications (wai-aria) 1.0 specification tabpanel , authoring practices guide state basic definition , how works, doesn't answer question "should screenreader speak contents of tabpanel when becomes visible?"

that example problematic in need convince business requirements shouldn't spoken, yet nothing says 1 way or other. (the best can point out examples authoring practices guide not spoken.)

for that, , half dozen other issues nice have guide says "this screen reader (or should do) when encounters element/role."

does exist?

there simple principles:

1. screen readers default start reading page in dom order beginning end. preceded basic stats of page such title , number of links, headings etc. users not allow screen reader read entire page , interrupt reading start navigating
2. if user knows page, choose way navigate things know on page. common navigation mechanisms headings, forms, landmarks, links, tables etc. if user not know page, may navigate , explore using different strategies similar way sighted user scan page eyes.
3. when user navigates, move virtual cursor. focus follow cursor jumping focusable element focusable element encountered (this configurable). screen reader read out whatever encounters user navigates this. akin sighted user scanning page read. key here user needs control read out navigating around. 1 caveat if user activates control causes other part of page updated , sighted user expect know has updated or know value, application should read out using aria-live.

as note, last point crosses technical accessibility usability realm. here common mis-conceptions novices hold.

1. you need make tab focusable screen readers: no not, screen reader can see without being tab focusable,
2. you need announce every update page: no not. if user interacting tab, know through experience, selecting tab expose contents , there keyboard commands content. not need tell them tab has been shown, need update selected state of tab.
3. you don't need announce anything: no, need decide information important enough announce automatically. example, if implementing chat application, dumb if user had navigate around hear messages have arrived friends. these should announced automatically.

i suggest bring blind screen reader user organization , have them demonstrate execs how things illustrate these points.