If focus can be moved to a component of the page using a keyboard interface, then focus can be moved away from that component using only a keyboard interface, and, if it requires more than unmodified arrow or tab keys, the user is advised of the method for moving focus away.
On this page:
Rationale
The intent of this checkpoint is to ensure that that content does not "trap" keyboard focus within subsections of content on a Web page. This is a common problem when multiple formats are combined within a page and rendered using plug-ins or embedded applications.
Required development techniques
Compliance with this checkpoint requires all of the following techniques be met. These techniques are defined in the WCAG 2.0 Level A Success Criterion for Guideline 2.1.2. (link resides outside of ibm.com)
1. No trap: Ensure that users are not trapped in content.
Examples for General developers
1. No trap: Ensure that users are not trapped in content.
Compliance with this checkpoint requires all of the following examples be met.
Example 1
Make sure that any applets launch in their own browser window. This helps to ensure that a user can exit or enter an applet or plug-in using the keyboard.
Example 2
Develop plug-ins in such a way that you can enter and exit the plug-in, such as a Flash object, using the keyboard. Plug-ins do not launch in a separate window.
For additional information, refer to WCAG 2.0 examples for ensuring that users are not trapped in content (link resides outside of ibm.com).
Examples for Adobe® Flash® developers
1. No trap: Ensure that users are not trapped in content.
Compliance with this checkpoint requires all of the following examples be met.
Example 3
Ensure that users are not trapped in content for Flash
Control the tab order and the reading order, and ensure that both are logical. The tab order determines which objects will receive focus when the tab key is pressed. The reading order is the order that the screen reader reads information about the object. Use the tabIndex property in ActionScript to set both the tab order and reading order.
More information on the tabIndex property can be found on the Adobe LiveDocs Website (link resides outside of ibm.com).
It is possible, but not recommended, to use the Tab Index text box in the Accessibility Panel (Adobe Flash CS3 Professional only) to set the tab order. If you choose to set the tab order using the Tab Index text box, you will still need to use ActionScript to set a tabIndex, which creates a clean reading order for the screen reader. In other words, you can set a tab order with the Accessibility Panel, but you can set both tab order and reading order with the more powerful ActionScript.
More information can be found on the Adobe Flash Accessibility Design Guidelines Website for Reading Order (link resides outside of ibm.com).
Examples for IBM® Lotus® Domino® developers
1. No trap: Ensure that users are not trapped in content.
Compliance with this checkpoint requires all of the following examples be met.
Example 4
Ensure that users are not trapped in content for Domino.
There is a known bug in Domino Designer 7 and Domino Designer 8 which prevents users from accessing content within sections. Until this problem is fixed, do not use sections to group and organize elements on a page or form.
This technique does not apply to Flash content added using Domino Designer. If Flash content is added to your Domino application, it must be developed in a way that allows a keyboard user to navigate in and out of the content.
Required test techniques
The following test tools and techniques are required to test this checkpoint.
Test tools:
Install the following tools to test this checkpoint:
Required accessibility verification test techniques:
Use the following accessibility verification test (AVT) techniques to validate the Web content. It is recommended that these tests be performed in order.
| Action | Result | |
|---|---|---|
|
Test the Web site with a Web syntax analyzer to verify the compliance criteria as follows:
|
Pass:
|
|
Use the following accessibility verification test (AVT) to validate the Web content. It is recommended that these tests be performed in order. |
| Action | Result | |
|---|---|---|
|
Verify the compliance criteria for this technique as follows.
|
Pass:
|
®2009 IBM Corporation
Last updated August 31, 2009.
W3C Recommendation 11 December 2008: http://www.w3.org/TR/WCAG20/ (link resides outside of ibm.com)
Copyright 1994-2009 W3C (Massachusetts Institute of Technology, European Research Consortium for Informatics and Mathematics, Keio University), All Rights Reserved.