The Web Content Accessibility Guidelines (WCAG) are an international standard developed to help web content creators ensure that their sites are accessible to everyone. These guidelines are organized into four fundamental principles: Perceivable, Operable, Understandable, and Robust (POUR).

In this chapter, we will learn about each of these principles, the levels of conformance, and how to apply them in our HTML projects.

What are the WCAG?

Image description: A summary of the WCAG accessibility principles with examples.

WCAG provides a set of recommendations for making websites accessible to people with disabilities. These guidelines cover visual, auditory, motor, and cognitive aspects.

The four foundational principles of WCAG

Perceivable

Content must be presented in a way that users can perceive it with at least one of their senses. This includes:

• Providing alternative text for images (alt in <img> tags).
• Offering captions and transcripts for multimedia content.
• Using proper contrast between text and background.

Example of using alternative text for an image:

html

Operable

Users must be able to interact with all site elements, whether with a keyboard, mouse, or other devices. Includes:

• Allowing keyboard navigation.
• Ensuring there are no elements with overly short interaction times.
• Avoiding content that can cause seizures, such as flashing animations.

Example of keyboard accessibility:

html

Understandable

Content must be easy to understand. This is achieved through:

• Clear and coherent language.
• Appropriate labels and instructions in forms.
• Avoiding unnecessary technical jargon.

Example of a clear and understandable form:

html

Robust

Content must be compatible with different browsers, devices, and assistive technologies, such as screen readers. This includes:

• Using valid tags and attributes.
• Testing the site across different browsers and devices.
• Avoiding dependencies on specific technologies.

Example of an ARIA attribute enhancing robustness:

html

Levels of Conformance: A, AA, and AAA

The WCAG defines three levels of conformance:

• Level A: Basic requirements that must be met for content to be accessible.
• Level AA: More stringent requirements that significantly enhance accessibility.
• Level AAA: Ideal standard, but difficult to fully implement.

Image description: A comparative graph of WCAG conformance levels with practical examples.

How to apply WCAG to your HTML projects

To effectively implement WCAG:

• Review each principle and apply it to your site using practical examples as shown in this chapter.
• Use tools like Lighthouse or Axe to assess your site's compliance.
• Conduct manual tests with devices and assistive technologies.

Conclusion

WCAG is an essential guide for any web developer aiming to create inclusive experiences. Applying these guidelines not only complies with legal standards in many countries but also improves the quality of your sites.

In the next chapter, we will explore the role of semantic HTML in accessibility and how we can use it to improve the structure and navigability of our projects. Join us!