Adobe Flash was an animation technology that allowed web developers to build dynamic content featuring multimedia and interactive applications.
Flash content is not accessible to all users, including screen reader users, mouse-free users, people who are deaf or hard of hearing, and other people with disabilities.
Over a number of years Adobe added limited accessibility features. For example, many Flash video players added support for closed captions, and the Flash authoring environment added functionality that could improve the experience for screen reader users and keyboard-only users in the Windows operating system. However, these features did not extend to other operating systems, nor were they comprehensive even in the Windows environment. For example, Flash does not support Windows high contrast mode nor users' text size settings. Although Adobe is committed to providing tools to develop accessible Flash tools, ensuring Flash accessibility can be difficult and time consuming.
Due to Flash not being able to offer comprehensive support to users of all operating systems and browsers it is prohibited from being used on public websites.