See Understanding Techniques for WCAG Success Criteria for important information about the usage of these informative techniques and how they relate to the normative WCAG 2.0 success criteria. The Applicability section explains the scope of the technique, and the presence of techniques for a specific technology does not imply that the technology can be used in all situations to create content that meets WCAG 2.0.
HTML and XHTML
This failure relates to:
meta
http-equiv of refresh is often used to periodically refresh
pages or to redirect users to another page. If the time interval is too
short, and there is no way to turn auto-refresh off, people who are blind will not have enough time to make their screen
readers read the page before the page refreshes unexpectedly and causes the
screen reader to begin reading at the top. Sighted users may also be
disoriented by the unexpected refresh.
This is a deprecated example that changes the user's page at regular
intervals. Content developers should not use this technique to
simulate "push" technology. Developers cannot predict how much time
a user will require to read a page; premature refresh can disorient
users. Content developers should avoid periodic refresh and allow
users to choose when they want the latest information. (The number
in the content attribute is the refresh interval in
seconds.)
Example Code:
<html xmlns="http://www.w3.org/1999/xhtml" lang="en">
<head>
<title>HTML Techniques for WCAG 2.0</title>
<meta http-equiv="refresh" content="60" />
</head>
<body>
...
</body>
</html>
(none currently listed)
Find meta elements in the document.
For each meta element, check if it contains
the http-equiv attribute with value "refresh" (case-insensitive) and
the content attribute with a number (representing seconds) equals to or greater than 0 and without "; url=" (case-insensitive).
check to see if there is a mechanism to turn off the refresh.
If step 2 is true and step 3 is false then this failure condition applies and content fails these Success Criteria.