Add context-sensitive help to form fields
A title attribute on a form control can carry extra guidance, a format hint or a worked example. W3C classes H89 as advisory, so it never satisfies a rule on its own, and attaches it to one criterion, 3.3.5 Help, at Level AAA. It also carries its own warning in four words. Avoid using this technique in isolation. The test procedure makes the same point structurally, because it checks for a properly associated visible label first and only then looks at the title. So H89 supplements a label and never replaces one. Where the guidance genuinely matters, visible hint text tied to the field with aria-describedby reaches everybody rather than only the people holding a mouse.
How we find it in an audit
There is nothing here for a scanner to find, because deciding a field needed help is a judgment. We look at the fields that reject what people type on format grounds, dates and reference numbers and phone numbers. Then we ask whether the format was stated anywhere a keyboard user or a phone user could have found it before pressing submit.
How affected users experience it
What a screen reader does with a title on a field varies. Some announce it after the label, some only in a particular mode, some not at all. Sighted keyboard users never see a tooltip and phone users have nothing to hover with. Help that only arrives for people holding a mouse misses a good share of the people who needed it, and visible hint text under the label reaches all of them.
Passes vs. fails
Passes
<label for="ref">Booking reference</label>
<input id="ref" aria-describedby="ref-hint">
<p id="ref-hint">Six letters, for example ABCDEF.</p>Fails
<label for="ref">Booking reference</label>
<input id="ref" title="Six letters, for example ABCDEF">The other techniques filed under this rule
6 guides on this site are filed under 3.3.5 Help. W3C lists this one as advisory for that rule rather than sufficient, which means it helps real readers without being accepted as evidence you conformed.
This guide is our interpretation of W3C technique H89: Using the title attribute to provide context-sensitive help. W3C publishes its techniques as guidance rather than as the standard, and says so on every one of them. The success criterion is what conformance is measured against, and a technique is one documented way to meet it.