Glossary · Accessibility term
Mechanism
A mechanism is a process or technique for achieving a result, and WCAG reaches for the word whenever it wants an outcome without prescribing a control. Seventeen success criteria use it. The mechanism does not have to be something you built, because the standard lets you rely on one the platform or the user agent already provides, which is why password manager support and copy and paste both count as ways of helping someone through a login. What the standard does not do is let the mechanism off. It has to meet every success criterion at the level you are claiming, so a pause button no keyboard can reach is not a mechanism for the purposes of the rule that asked for one.
In practice
When a rule asks for a mechanism, you are being asked for an outcome and left to choose the method. A visible control, a keyboard shortcut, a link to another page carrying the thing, or a capability you simply did not block can all count. Under Consistent Help a published phone number is a mechanism, which shows how far past interactive controls the word reaches.
The method is open and the quality bar is not. Where you build the mechanism yourself it is content on the page, so it has to pass everything the page has to pass. Test it the way you test the rest of the page. Reachable by keyboard, visible when it takes focus, named so a screen reader can announce it, and readable at the contrast the level demands. Where the mechanism is the platform's or the browser's, the question changes to whether it is genuinely available to your reader, and the thing to check is that nothing in your code has switched it off.
Why it matters
It is why two sites can meet the same rule in different ways and both be right, and why an auditor insisting on one specific control is overreaching. It is also the word that lets a failure ship looking like a pass. Something was provided, a box was ticked, and nobody checked whether the thing provided could be operated by the people the rule was written for.
Two ways to satisfy one rule
2.2.2 asks for a mechanism to pause, stop or hide moving content that starts on its own, runs past five seconds and sits alongside other content, unless the movement is essential to the activity. A control on the page that stops the movement satisfies it. So does one that pauses and then resumes from the point it was paused, which suits a news ticker where the reader does not want to lose the items that went by. Honouring the reduced-motion setting is a different kind of answer and W3C does not list it as a sufficient route here, so treat it as something worth doing rather than as the thing that closed the finding.
Where this shows up on the site
Related terms
- EssentialEssential is the word sixteen success criteria use to carve out the cases where meeting them would change what is actually on offer.
- User agentA user agent is any software that retrieves and presents web content, which takes in browsers, media players, plug-ins, and assistive technology as well.
Knowing the word is the easy part.
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