Proposal: Provide better advice on constraint validation instructions

Hi all,

a while back I submitted a bug about the HTML spec recommending the use of
the title attribute for instructions[1]

"the spec suggests user agents use the title attribute for description
strings that may be displayed at any time. Due to user agents not
implementing 'tooltips' accessibly, the content is not available to
keyboard only users until an incorrect pattern has been put in.

I am proposing to add/modify advice and code examples (in the relevant
section [2]) on how to provide instructions to users, that are not reliant
upon the use of the title attribute.

The methods I am going to recommend all involve adding the instructions in
text either as part of the label or associated vi aria-describedby :

example using the label
<label> Part number:
 <input pattern="[0-9][A-Z]{3}" name="part">
A part number is a digit followed by three uppercase letters. </label>

example using aria-describedby

<label> Part number:
 <input pattern="[0-9][A-Z]{3}" name="part" aria-describedby="instructions">
 </label>

<p id="instructions"> A part number is a digit followed by three uppercase
letters.</p>


I envisage that this advice can be modified to recommend use of the title
attribute at a time when it is interoperably implemented in an input device
independent way.

[1] https://www.w3.org/Bugs/Public/show_bug.cgi?id=16835
[2]
http://www.w3.org/html/wg/drafts/html/master/forms.html#attr-input-pattern

feedback welcome!

with regards

SteveF <http://www.paciellogroup.com/resources/wat-ie-about.html>
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