Glossary · Accessibility term
Live region
A live region is a part of the page marked so that assistive technology announces changes to it without the user having to go and look. A cart total updating, a save confirmation, a search count, a validation error appearing. Without one, all of that is silent, and somebody who cannot see the page clicks, hears nothing, and has no way to know whether it worked. The mechanical detail that decides whether yours works is the word changes. Assistive technology conveys changes to a live region rather than whatever was in it when the region first rendered, so the container has to exist on the page before the message arrives in it. Inject a fresh div with the message already inside and usually nothing is announced. The alert role is the deliberate exception, because ARIA asks the browser to raise a system alert event when one is created. Everything else is why so many developers decide live regions are unreliable, when what really happened is that the region and its content turned up together.
In practice
Polite is nearly always the right setting. It waits for a gap, such as the end of the sentence being spoken, and it does not throw anybody off what they were doing. Assertive asks for immediate notification, and the specification tells authors not to use it unless interrupting is imperative, because an interruption can disorient somebody or stop them completing a task. There is a harder consequence too. An assertive announcement can clear the queue, so the polite messages somebody was waiting to hear are destroyed by the urgent one. Note the word asks. ARIA calls politeness a strong suggestion rather than a command, and says in terms that a user agent, an assistive technology or the user can override what you set.
The roles are shorthands with extra behaviour attached rather than plain aliases. A status region is polite and also atomic by default, so the whole region gets read on every change, where a bare polite div reads only the part that changed. That is the difference between hearing 3 items in cart and hearing 3. An alert region is assertive and atomic, and it is the one exception to the timing rule, because it announces when it is rendered as well as when it changes.
Restraint is a real requirement here and there is a rule shaped like it. Announcing something and also moving focus to it announces the same thing twice, because moving focus is a change of context and sits outside the status message rule entirely. Pick one route per message. The boundary is narrower than people assume as well, since a list of search results is not a status message while the words 18 results returned are.
Why it matters
Dynamic pages are where accessibility quietly stops working, because everything that used to be a page load is now a silent repaint. The rule covering this is Level AA and it exists for exactly that reason. It is also the joint between accessibility and the rest of your product. The same missing announcement that fails an audit is why somebody adds one item to their cart three times. The failure mode in the other direction is just as real. A page that announces every hover, every scroll and every re-render buries the one message that mattered, and the reader's only way out is to turn something off and lose the rest with it. Announce once, and mean it.
The bug that makes people give up on live regions
A developer writes a search that inserts a div carrying an aria-live attribute and the words 3 results found, tests it with a screen reader, hears silence, and concludes the feature does not work. It works. The region has to be on the page first, and the words have to arrive into it afterwards. Two lines in a different order, and the same code starts speaking.
Where this shows up on the site
Related terms
- ARIAARIA is a set of attributes that tell assistive technology what a custom control is and what state it is in.
- Error identificationError identification is the Level A rule that when your form rejects something, the page names the field that failed and says in text what went wrong.
- Screen readerA screen reader is software that reads the screen out loud, or sends it to a braille display, for people who cannot see it.
- RobustRobust is the fourth of WCAG's four principles, and it asks that content be built well enough for a wide variety of user agents, including assistive technology, to interpret it.
- Toast notificationA toast notification is a short message that appears, usually to confirm something worked, and takes itself away on a timer.
- Status messageA status message is a change in content that tells you how something went, without moving focus to it.
- alertdialogAn alertdialog is a dialog that interrupts, and it is the role for a message somebody has to answer before anything else happens.
Knowing the word is the easy part.
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