Overview of the accessibility of Flash

Adobe Flash content can be viewed on almost all computers. Flash technology, in a general sense, is perhaps the most widely used Web. For developers, the ability to program a multimedia presentation that can be displayed identically on almost all computers makes this technology very attractive. However, for people with disabilities, Flash can introduce serious problems of accessibility.

Due to the nature of Flash multimedia, it can be used to provide content across multiple mediums: graphics, text, video, audio, etc.. Its power and flexibility give it the potential to make Web content fully accessible manner. Some examples of how Flash can increase accessibility:

• Multiple presentation of the same information: Flash can present content in different ways. See an example of a multiple presentation of the same information ( ).
• Magnification without distortion: because Flash is based on vector objects (mathematically defined lines and shapes) rather than a fixed technology (adding pixels of different colors), Flash content can more easily be manipulated to any What size and without distortion. People with low vision may be able to interact with Flash content while they could not do with HTML content. See example ( ).
• Keyboard Accessibility: Flash allows a higher level of interaction than permitted keyboard in HTML. Flash animations can be made ​​more functional, powerful and easy to use by providing access to the keyboard. See example on the keyboard ( ).
• Attractiveness: Flash can increase the attractiveness of content with interactivity, animations, sounds, graphics, and many other features. People with learning disabilities or cognitive impairment can better understand and focus on some Flash content. The Flash multimedia can be used to supplement the static HTML content.
• Audio feature: audio thanks to the possibilities of Flash, it can present content in the audio and thus to eliminate the need for a screen reader to listen to the content in a Flash movie.

The key points of accessibility of Flash

Despite the ability of Flash to create content very accessible, there are major issues which you should be aware regarding Flash and accessibility. Almost all the principles regarding the accessibility of HTML may also apply to Flash. These include using a lot of contrast, to have a consistent navigation, understandable language, etc.. Here are some specific strategies for making Flash accessible to different types of disability:

• Hearing impairment
  • Put subtitles synchronized at all audio information which vehicle.
• Photosensitive epilepsy
  • Remove any content strobe which the frequency of occurrence is between 2 and 55 times per second.
• Motor disability
  • Visit the Flash content available on the keyboard.
  • Do not require fine motor skills to perform an action.
• Cognitive impairment
  • Give users control over the temporal content.
  • Provide easy to use controls and navigation patterns.
  • Be consistent.
  • Use language appropriate for the content that is as clear and simple.
• Low Vision
  • Provide strong contrasts.
  • Allow Flash content to adapt to a larger size.
• Blindness
  • Ensure accessibility to screen readers or provide an accessible alternative.
  • Allow access to the keyboard.
  • Do not create features that interfere with the audio screen readers or keyboard commands.
  • Provide text equivalents for all non-text elements that convey content or create a feature.

Although each of these strategies can increase accessibility, Flash content is rarely designed to include all of these strategies simultaneously, making it inaccessible to some extent. When all accessibility techniques are applied to Flash, it can be universally accessible, perhaps more than HTML, because the need for specific assistive technologies (with their own limits support) is deleted. However, such an objective would be difficult or impossible with most Flash content. In short, unless all accessibility techniques are applied, the Flash may not be accessible.

What is the degree of accessibility to Flash assistive technologies?

By its very nature, Flash content does not lend itself to accessibility to the screen reader. Flash content is held in time and it often changes over time. HTML content is more or less static. The static nature of HTML allows a screen reader to access the HTML content in a linear fashion. When a user accesses a Flash movie visually, he or she visually scans the content of the film and focuses directly on the important content or functionality. A screen reader user can not "scan" the Flash content. It can be accessed only linearly in the order in which the Flash developer has chosen to present it. Flash and the duration of the programming language (ActionScript) allow continuous change, dynamism, the updating of objects to animate, move, or disappear or replicate every time the Flash developer chooses (or even chance, if he wants). Because Flash content is constantly changing, this limits the ability of the screen reader to read the contents of a sufficiently or in time.

Despite the problems that can cause Flash to users of screen readers, there are techniques accessibility that can be implemented to make Flash more accessible. Microsoft Active Accessibility (MSAA) is used to send content from the Flash player to the screen reader. MSAA is a Microsoft technology that works for now only with Internet Explorer on Windows computers that have Flash player version 6 or higher recent installed. Although most assistive technologies tend to be implemented on Windows with Internet Explorer, screen readers running on other platforms can not benefit from the accessibility features of Flash. There are several screen readers that run on other operating systems. Someone with a mobility impairment may not use Internet Explorer. In addition, your end user may not have the latest version of Flash player installed. In fact, they may not have Flash installed at all. Many users of screen readers have disabled Flash content because of the vast amount of content inaccessible Flash Flash on the Web.

In summary, you must test users with a variety of end users, platforms, browsers and assistive technologies to ensure that your Flash content is accessible to the widest possible range of users. You may need to re-evaluate your use of Flash. Perhaps another technology may be more appropriate. As the vast majority of Flash content can not be made available natively, it will probably be essential to provide an alternative non-flash for those who can not or will not access your multimedia Flash.

Accessible via a screen reader

There are 3 ways to make Flash content accessible to screen reader users:

1. Visit the Flash content natively accessible to screen reader.
2. Visit the Flash content self-sufficient in terms audio, eliminating the need for a screen reader.
3. Provide an accessible alternative to Flash content.

By making your Flash movie self-sufficient in terms audio, you remove the need for a screen reader. In essence, you take the role of screen reader by transmitting any audio content that is presented visually in the Flash movie. Users of screen reader must be warned that the program has audio capabilities so that the screen reader can be paused while the Flash movie has audio content. All content is conveyed visually important must also be provided by the audio. This is what is done when listening to a sporting event on the radio - although you can not see the action, commentators describe orally you all the important details. You may wish to provide a sound film as an alternative to a Flash movie with audio insufficient, or provide an option to disable or enable audio. Remember: if you send an audible content that is not apparent, you must provide captions for the deaf and hard of hearing. The film must also be accessible via the keyboard.

It is also important to provide an equivalent alternative to the Flash movie itself. This should be done only when the film itself can in no way be accessible to all. It can be difficult to justify an HTML tutorial is the equivalent of an interactive multimedia Flash. The key is equivalent to the alternative content, not necessarily to give the text only. Instead of providing a page with large text lengths, the equivalent would be a nicely formatted Web page, accessible with images, icons, and color paragraphs. Simply because when someone accesses your equivalent alternative, does not mean he is blind and does not care about the visual of the page or how it works. Often, the alternative may be in the same page as the Flash movie itself. In some cases, you can give the user the possibility to switch on and off the Flash content.