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Sip and puff input system for people with limited movement. Macromedia Flash is often used to create visually-intriguing and interactive Web sites. Flash objects, or movies, can deliver information in a variety of ways, including text, audio, video, and animation. Flash content can also be used as navigational elements, banner advertisements, illustrative aids, online forms, and for other Web page components. Flash content is vector-based and scalable, with an amazing zoom capability which permits the movie to be viewed at nearly any size without distortion.
Because it is such a versatile multimedia format, Flash has the potential to offer advantages or disadvantages for people with disabilities, depending on how the movie is created. If Flash is carefully designed, it can be made accessible to screen reader users and other people with disabilities. However, this requires a combination of designer skill and a compatible user viewing platform.
The following conditions must be met for a person to access the Flash content on your Web site if they are using a screen reader or speech synthesizer software:
These restrictions can make it difficult for screen reader users to simply access your Flash content, much less interact with it.
It is also important to remember that the Flash player, while free, is still a proprietary browser plug-in. This means that Flash content itself is not natively accessible like HTML. Reliance on any proprietary platform or technology will automatically exclude some visitors from your Web site. Unless you intend to provide an identical, non-Flash version of your Web site, Flash should not be used to create an entire Web site. The best use of Flash is when it supplements the content on your Web site, for illustrative or interactive uses, rather than for essential page elements such as navigation, online forms, etc.
If you choose to use Flash on your Web site, it is critical that you test your Flash design early and often. Flash designers themselves should be very comfortable with using a screen reader so that they can test their own movies. Additionally, user testing must be conducted to ensure that the design is compatible with a variety of platforms, browsers, and assistive technologies. Regardless, you will likely still need to provide a non-Flash alternative for those that cannot or choose not to access your Flash multimedia.
When a web page requires that an applet, plug-in or other application be present on the client system to interpret page content, the page must provide a link to a plug-in or applet that complies with §1194.21(a) through (l). [Section 508, Part 1194.22, Paragraph (m)]
Equivalent alternatives for any multimedia presentation shall be synchronized with the presentation. [Section 508, Part 1194.22, Paragraph (b)]
Pages shall be designed to avoid causing the screen to flicker with a frequency greater than 2 Hz and lower than 55 Hz. [Section 508, Part 1194.22, Paragraph (j)]
Until user agents allow users to control flickering, avoid causing the screen to flicker. [W3C WCAG 1.0, Checkpoint 7.1 Priority 1]
Provide a text equivalent for every non-text element (e.g., via "alt", "longdesc", or in element content). This includes: images, graphical representations of text (including symbols), image map regions, animations (e.g., animated GIFs), applets and programmatic objects, ASCII art, frames, scripts, images used as list bullets, spacers, graphical buttons, sounds (played with or without user interaction), stand-alone audio files, audio tracks of video, and video. [W3C WCAG 1.0, Checkpoint 1.1 Priority 1]
Until user agents can automatically read aloud the text equivalent of a visual track, provide an auditory description of the important information of the visual track of a multimedia presentation. [W3C WCAG 1.0, Checkpoint 1.3 Priority 1]
For any time-based multimedia presentation (e.g., a movie or animation), synchronize equivalent alternatives (e.g., captions or auditory descriptions of the visual track) with the presentation. [W3C WCAG 1.0, Checkpoint 1.4 Priority 1]
Several detailed tutorials exist for creating accessible Flash movies. These are written for experienced Flash designers. Visit the links at the end of this document to explore these techniques for adding text equivalents, text captioning, keyboard access, proper tab order, etc.
In addition to designing your movie to be accessible to screen reader users, it is important to remember that most general accessibility guidelines that apply to HTML content also pertain to Flash content:
If your Flash movie contains audio elements other than music, the movie must be captioned, and the captioning must be synchronized with the movie. The MAGpie Captioner for Flash is available from the National Center for Accessible Media, a sub-group of WGBH.
Here is information about this technique from WebAIM.org:
By making your Flash movie self-voicing, you remove the need for the screen reader. In essence, you are taking over the role of the screen reader by conveying audibly any content that is presented visibly within the Flash movie. The screen reader user should be alerted that the program is self-voicing so the screen reader can be paused while the Flash movie presents the audio content. Any important content that is conveyed visibly must also be provided through the audio. You can relate this to listening to a sports event on the radio - although you cannot see the action, the commentators are providing all of the important details through the audio. You may want to provide a self-voicing movie as an alternative to a non-voicing Flash movie, or provide an option to turn self-voicing functionality on or off. Remember, if you are conveying any content audibly that is not apparent from the visible display, you must provide captions for the Deaf and hard of hearing. The movie must also be made keyboard accessible.
Some Flash content may be decorative in nature, or the content of the movie may be available elsewhere on the same page. In these cases, it may be appropriate to hide the Flash object from keyboard access. Sometimes keyboard users with older versions of the Flash payer can become stuck within the Flash movie, which prevents them from navigating to other elements on the page. WebAIM.org offers information about how to do this in their Accessible Flash Tutorial. This technique does not hide the Flash movie on the page - sighted users can still see the content. Rather, it permits keyboard and screen reader users to easily skip past the movie as if it were not present on the page.
If you include a Flash movie, include a link on the same page to Macromedia's Flash Player. For example:
Some features on this page require the free
Macromedia Flash Player plug-in for viewing.
