Techniques for WCAG 2.0

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FLASH3: Marking objects in Flash so that they can be ignored by AT


This technique relates to:

User Agent and Assistive Technology Support Notes

See User Agent Support for Flash for general information on user agent support.


The purpose of this technique is to show how images can be marked so that they can be ignored by Assistive Technology.

The Flash Player supports the ability for authors to control which graphics appear to assistive technologies using the silent property of the accessibility object, as indicated in the examples below.


Example 1: Hiding a graphic in the Flash Professional authoring tool

The Flash Professional authoring tool's Accessibility panel lets authors provide accessibility information to assistive technology and set accessibility options for individual Flash objects or entire Flash applications.

  1. To apply changes to accessibility properties for a graphic, it must be saved as a symbol in the movie's library. Note: Flash does not support text alternatives for graphic symbols. Instead, the graphic must be converted to or stored in a movie clip or button symbol.

  2. Bring up the accessibility panel by selecting "Window > Other Panels > Accessibility" in the application menu, or through the shortcut ALT + F11.

  3. Select the graphic object

  4. If the 'Make object accessible' checkbox in the accessibility control panel is checked, uncheck this option to remove the graphic from the accessiblity information conveyed to assistive technologies.

Example 2: Applying textual alternatives programmatically in ActionScript 2.0

To manage an object's text equivalents programmatically using ActionScript, the _accProps property must be used. This references an object containing accessibility related properties set for the object. The code example below shows a simple example of how the _accProps property is used to remove an object from the accessibility information for the movie using ActionScript.

Example Code:

// 'decorative_mc' is an instance placed on the movie's main timeline
_root.decorative_mc._accProps = new Object();
_root.decorative_mc._accProps.silent = true; 


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  1. Publish the SWF file

  2. Open the SWF file in Internet Explorer 6 or higher (using Flash Player 6 or higher), or Firefox 3 or higher (using Flash Player 9 or higher)

  3. Use a tool which is capable of showing an object's accessibility information, such as aDesigner2 to open the Flash movie.

  4. In the GUI summary panel, loop over each object which is contained by the Flash movie and ensure the object that was designed to be hidden does not appear in the tool's display.

  5. Authors may also test with a screen reader, by reading the Flash content and listening to hear that object is not mentioned when the page is read.

  6. Non-text objects that are coded to be hidden from assistive technologies are not available to assistive technology.

Expected Results

Check #6 is true.

If this is a sufficient technique for a success criterion, failing this test procedure does not necessarily mean that the success criterion has not been satisfied in some other way, only that this technique has not been successfully implemented and can not be used to claim conformance.