2.28 Do not periodically auto-refresh pages
Contents
WAI checkpoint 7.4
Full WAI text: "Until user agents provide the ability to stop the refresh, do not create periodically auto-refreshing pages."
User agents are software which people use to access Web content. These include graphical browsers, text-only browsers, voice browsers, mobile phones, multimedia players, plug-ins and assistive technologies such as screen readers, screen magnifiers and voice recognition software.
It is possible to create pages which automatically reload in the user's browser every so often, as long as the browser window is open. This should be avoided at present, since not all user agents allow the user to disable auto-refresh.
Rationale
Automatically reloading a new page, or the same page with new content, can be very confusing and frustrating for users who may not be overly familiar with computers and using the web. Many people find auto-refreshing pages highly confusing because they take control of navigation away from users, who can quickly become disoriented and fail to grasp the structure of a site.
Users read at different rates. It is highly disruptive and unsettling if the page refreshes before the user has had a chance to either determine the content of the page, or before they finish reading it. This can make pages or content unusable for users who have limited reading ability or difficulty concentrating because of noise, stress or a learning disorder. Auto refresh also causes problems for users of screen readers, which generally cannot cope with auto-refresh and may fail to show any content at all.
Directions and Techniques
Provide a mechanism or control for disabling auto-refresh
If you create auto-refreshing pages using Java applets or other techniques, you should provide an obvious control which allows the user to control the rate of refresh or to disable page refreshing altogether.
Avoid using the META element for auto-refresh
See the WAI description of why META should not be used to redirect or auto-refresh pages
How you could check for this:
There are no specific test methods recommended for this guideline.
Guidelines for Web Accessibility - Priority 2- 2.1 Ensure that images have sufficient contrast for people with colour deficient vision
- 2.2 Avoid causing content to blink
- 2.3 Avoid movement in content
- 2.4 Ensure that dynamic content is accessible or provide an alternative presentation or page
- 2.5 Use style sheets to control layout and presentation
- 2.6 Use relative rather than absolute units
- 2.7 Use header elements to convey structure
- 2.8 Break up large blocks of information where appropriate
- 2.9 Ensure that information laid out using tables make sense when linearised, or provide an alternative equivalent
- 2.10 Do not use structural mark-up to format information laid out using tables
- 2.11 Describe the purpose of frames and how they relate to each other if it is not obvious by their titles alone
- 2.12 Clearly identify the target of each link
- 2.13 Provide information about pages and sites in metadata
- 2.14 Provide information about the general layout of a site
- 2.15 Use navigation mechanisms consistently
- 2.16 Associate labels explicitly with their controls
- 2.17 Properly position the labels of form controls
- 2.18 Ensure that user interfaces are device-independent
- 2.19 Use logical event handlers in scripts
- 2.20 Use input device-independent event handlers in scripts and applets
- 2.21 Ensure that scripts and applets are accessible
- 2.22 When an appropriate markup language exists, use markup rather than images to convey information
- 2.23 Create documents that validate to published formal grammars
- 2.24 Mark up lists and list items using the proper HTML tags
- 2.25 Use quotation mark-up for quotations, but not for formatting
- 2.26 Where possible, use appropriate W3C technologies of the latest supported versions
- 2.27 Avoid deprecated features of W3C technologies
- 2.28 Do not periodically auto-refresh pages
- 2.29 Do not use mark-up to redirect pages automatically
- 2.30 Do not generate pop-ups or other windows and do not change the current window without informing the user
