Making Websites and Applications Accessible

Accessibility Principles

The W3C’s Web Accessibility Initiative manages the international Web Content Accessibility Guidelines . These guidelines are organized around four basic principles that lay the foundation necessary for anyone to access and use digital web-based content. Anyone who wants to use our products and systems must have content that conforms to these principles:

  1. Perceivable - “Information and user interface components must be presentable to users in ways they can perceive. This means that users must be able to perceive the information being presented (it can't be invisible to all the senses they’re able to use).” Examples include text alternatives for non-text content; captions and other alternatives for multimedia; content can be presented in different ways; content is easier to see and hear.
  2. Operable - “User interface components and navigation must be operable. This means that users must be able to operate the interface (the interface cannot require interaction that a user cannot perform).” Examples include functionality that is available from a keyboard; users having enough time to read and use the content; content that does not cause seizures and physical reactions; users can easily navigate, find content, and determine where they are; users can use different input modalities beyond a keyboard.
  3. Understandable - “Information and the operation of user interfaces must be understandable. This means that users must be able to understand the information as well as the operation of the user interface (the content or operation cannot be beyond their understanding).” Examples include text that is readable and understandable; content that appears and operates in predictable ways; users are helped to avoid and correct mistakes.
  4. Robust - “Content must be robust enough that it can be interpreted reliably by a wide variety of user agents, including assistive technologies. This means that users must be able to access the content as technologies advance (as technologies and user agents evolve, the content should remain accessible).” Examples include content that is compatible with current and future user tools.
  5. Integration and Compatibility

    Many aspects of accessibility are fairly easy to understand and implement, while other accessibility solutions are more complex and take more knowledge to implement. It is most efficient and effective to incorporate accessibility from the very beginning of projects to reduce development re-work.

    The accessibility of websites and applications depends on several components working together. These components include, but are not limited to:

    • Content - the information in a web page or web application, including natural information such as text, images, and sounds; code or markup that defines structure, presentation, etc.
    • Web browsers, web apps, media players, and other “user agents”
    • Assistive technology, in some cases - screen readers, alternative keyboards, switches, scanning software, etc.
    • User - knowledge, experiences, and in some cases, adaptive strategies using the web
    • Developers - designers, coders, authors, etc., including developers with disabilities and users who contribute content
    • Authoring tools - software that creates websites and applications
    • Evaluation tools - web accessibility evaluation tools, HTML validators, CSS validators, etc.

    The W3C Web Accessibility Initiative (WAI) develops technical specifications , guidelines , techniques , and supporting resources that describeaccessibility solutions. These are considered international standards for web accessibility. Please see our Accessibility Guidance for Assessment page for further detail.

    Evaluating Accessibility

    When developing or redesigning a website or application, it is important to evaluate accessibility early and throughout the development process. When accessibility problems are identified early on, they are easier to address. There are many development and testing tools available that can help you evaluate certain aspects of accessibility. Some of these tools are automated, while others require manual interpretation. A comprehensive evaluation to determine if a website or application meets all accessibility guidelines generally takes more time and effort but is worth the investment to effectively create a product or solution that works well for everyone.

    Maintaining Accessibility

    While making a new or existing product accessible is a big win for people who use our products and services, it is also extremely important to ensure that our products remain accessible as subsequent versions are released, and new technologies enter the market. Regular reviews of content, platforms, organizational processes, documentation, and resources will help ensure that accessibility remains a priority. Developing a management and reporting process will help ensure that accessibility issues are identified and addressed as a regular part of product development and maintenance. Some examples of accessibility maintenance include:

    • Monitoring websites and applications. Changes to content, features, and tools can introduce accessibility issues, and provide opportunities for improvement. Monitor changes to identify issues and solutions.
    • Engage with stakeholders. Work with all stakeholders to continually prioritize accessibility in product roadmaps and testing procedures.
    • Track standards and legislation. Stay informed about changes to guidelines and laws to ensure that you are responding to the latest requirements.
    • Adapt to new technologies. Update resources and websites in response to changes in web technologies and to the specialized tools people may use to access content.
    • Incorporate user feedback. Invite user feedback, including users with disabilities. Use this feedback to guide improvement activities and to identify areas in need of attention.