1. Perceivable - Information and user interface components must be presentable to users in ways they can perceive, meaning that the information being presented cannot be invisible to all of a user’s senses. This principle is further demonstrated in the following examples.

1.1 Text alternatives: Provide text alternatives for any nontext content so that it can be changed into other forms
that people need, such as large print, braille, speech, symbols, or simpler language.

1.2 Time - based media: Provide alternatives for time - based media, including captions and alternatives for audio and video content.

1.3 Adaptable: Create content that can be presented in different ways (e.g., simpler layout) without losing information or structure; in other words, all content should be accessible through the use of assistive technologies.

1.4 Distinguishable: Use sufficient contrast to make it easier for users to see and hear content, including separating the foreground from the background.

2. Operable - User interface components and navigation must be operable, meaning that users must be able to operate the interface and that the interface cannot require interaction that a user cannot perform.

2.1 Keyboard accessible: Make all functionality available from a keyboard; that is, all functionality should be keyboard accessible.

2.2 Enough time: Provide users enough time to read and use content.

2.3 Seizures: Do not design content in a way that is known to cause seizures.

2.4 Navigable: Provide ways to help users navigate, find content, and determine where they are; in other words, actively provide tools that help users to navigate and find content.

3. Understandable - Information and the operation of user interface must be understandable, meaning that the information and the operation of the user interface cannot be beyond their understanding.

3.1 Readable: Make text readable and understandable.

3.2 Predictable: Make content appear and operate in predictable ways.

3.3 Input assistance: Help users avoid and correct mistakes.

4. Robust - Content must be robust enough so that it can be interpreted reliably by a wide variety of user agents, including assistive technologies, meaning that users must be able to access the content as technologies advance and evolve.

4.1 Compatible: Maximize compatibility with current and future user agents, including assistive technologies.

The Web links below are online tutorials that will show you examples what a webpage should look like to be compliant with Section 508 of the Rehabilitation Act Web Accessibility of 1973.

1. Jim Thatcher
2. Web-based Intranet and Internet Information and Applications (1194.22)

Usability.gov is a one-stop source for government web designers to learn how to make websites more usable, useful, and accessible. The site addresses a broad range of factors that go into web design and development. The site will help you to:

• Plan and design usable sites by collecting data on what users need
• Develop prototypes
• Conduct usability tests and write up results
• Measure trends and demographics