For moving, blinking, scrolling, or auto-updating information, the user can pause, stop, hide or adjust the information. (Level A)

Rationale

The intent of this checkpoint is to avoid distracting users during their interaction with content. There are two basic directives:

  1. Moving, blinking, scrolling: For any moving, blinking or scrolling information that (1) starts automatically, (2) is presented in parallel with other content, and (3) lasts more than five seconds, there is a mechanism for the user to pause, stop, or hide it; and
  2. Auto-updating: For any auto-updating information that (1) starts automatically and (2) is presented in parallel with other content, there is a mechanism for the user to pause, stop, or hide it, or to control the frequency of the update.

"Moving, blinking and scrolling" refers to visible content that conveys a sense of motion. Common examples include videos, synchronized media presentations, animations, real-time games, and scrolling stock tickers.

"Auto-updating" refers to content that updates or disappears based on a preset time interval. Common auto-updating content includes audio, automatically updated weather information, news, stock price updates, and auto-advancing presentations and messages.

For all these types of content, the user requires the ability to pause, stop, or hide the content. In addition, for autoupdating, authors have the option of providing the user with a means to control the frequency of updates.

Content that moves or updates automatically can be a barrier to anyone who has trouble reading stationary text quickly, as well as anyone who has trouble tracking moving objects. It can also cause problems for screen readers which may not be able to verbalize all of the text before it gets updated; the user can lose their place in the text if the updates happen in the middle of reading the text.

Moving content can also be a severe distraction for some people. Certain groups, particularly those with attention deficit disorders, find blinking content distracting and have difficulty concentrating on other content. The five-second limit is long enough to get a user's attention, but short enough for a user to wait out the distraction before reading the page.

Note: For requirements related to flickering or flashing content, refer to WCAG Guideline 2.3.

Note: Since any content that does not meet this success criterion can interfere with a user's ability to use the whole page, all content on the Web page (whether it is used to meet other success criteria or not) must meet this success criterion. See WCAG Conformance Requirement 5: Non-Interference.

Essential Exception: If the movement, blinking, scrolling or autoupdating is part of an activity where it is essential, this checkpoint does not apply. An animation that occurs as part of a preload phase or similar situation can be considered essential if interaction cannot occur during that phase for all users and if not indicating progress could confuse users or cause them to think that content was frozen or broken.

Refer to Understanding SC 2.2.2 for more information (external link to WCAG).

Development Techniques

Review the General techniques as well as other tabs applicable to your technology.  Prioritize the use of technology-specific techniques, and implement the General techniques as needed. You are always required to find, understand and implement accessible code techniques to meet the checkpoint. The documented techniques and supplements are not exhaustive; they illustrate acceptable ways to achieve the spirit of the checkpoint. If numbered, techniques are in order of preference, with recommended techniques listed first. Where used, IBM information that complements the WCAG techniques is indicated as supplemental.

Web (HTML, ARIA, CSS) techniques

Instructions: In addition to the General techniques, any item in this section represents a technique deemed sufficient to address particular circumstances.

Meet G11: Creating content that blinks for less than 5 seconds with:

Mobile Native (iOS) techniques

In addition to the General techniques, any item in this section represents a technique deemed sufficient where applicable.

See the Progress Indicators section of the iOS Human Interface Guidelines for a discussion of providing status with activity indicators and progress bars. Links to development techniques are provided.

Eclipse techniques

There are no specific Eclipse techniques for this checkpoint. Refer to the General techniques section.

Windows-based (MSAA+IA2) techniques

There are no specific Windows-based techniques for this checkpoint. Refer to the General techniques section.


Most links in this checklist reside outside ibm.com at the Web Content Accessibility Guidelines (WCAG) 2.0. W3C Recommendation 11 December 2008: http://www.w3.org/TR/WCAG20/

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