Introduction to Accessibility

Published on February 25, 2007

Web accessibility refers to how usable a website is to people with disabilities.

People with disabilities have unique needs on the web. For example, blind people may use screen readers – special browsers that read aloud the text contents of a website – to browse the web. People with learning difficulties may need the contents of a website written in a simple way.

In order to cater to these needs, special considerations must be made when designing websites. Fortunately, there are guidelines to help designers create accessible websites.

Web Content Accessibility Group (WCAG)

The WCAG is a set of guidelines that explain how to create accessible websites. It has 14 guidelines.

Each guideline has one or more checkpoints. These checkpoints explain how the guideline applies in a web development scenario. There are 65 checkpoints.

Each checkpoint is assigned a priority level. This indicates the level of impact the checkpoint has to overall accessibility. There are three priority levels: 1, 2, and 3:

Priority 1

A Web content developer must satisfy this checkpoint. Otherwise, one or more groups will find it impossible to access information in the document.

Priority 2

A Web content developer should satisfy this checkpoint. Otherwise, one or more groups will find it difficult to access information in the document.

Priority 3

A Web content developer may address this checkpoint. Otherwise, one or more groups will find it somewhat difficult to access information in the document.

A website's level of conformance to the WCAG is determined by the following:

  • Conformance Level A – meets all Priority 1 Checkpoints
  • Conformance Level AA – meets all Priority 1 and 2 Checkpoints
  • Conformance Level AAA – meets all Priority 1, 2, and 3 Checkpoints

Here are a few examples of the WCAG checkpoints:

At the very least, web designers should aim for Conformance Level A when building their websites.

Section 508

Section 508 is the law that requires the Federal agencies to buy information technology that is accessible. These technologies include:

  • Software applications and operating systems
  • Web-based intranet and internet information and applications
  • Telecommunications products
  • Video or multimedia products
  • Self-contained closed products such as copiers
  • Desktop and portable computers

The Section 508 provisions are similar to those found (mostly) in Priority 1 Checkpoints of the WCAG. For example, Section 508 has provisions for the use of style sheets and text equivalents for images.

In some cases, though, the Section 508 provision is more restrictive than the WCAG. An example is WCAG Checkpoint 7.1 and Section 508 1194.22(j). The WCAG has a general recommendation against causing screens to flicker. Section 508 states specifically state a frequency range for that flickering: between 2 Hz and 55 Hz.

Section 508 does not apply to Federal agencies only. In some cases, private entities dealing with Federal agencies are subject to this law.


Designing an accessible website has more to offer than just providing access to people with disabilities. It also benefits your business in several ways.

  1. Great Web Experience

    Keeping information about your business open to all widens your reach. A wider audience means a larger pool of potential customers.

    Accessibility naturally enhances your website's usability. By following accessibility guidelines, websites become more readable, easier to navigate, and faster to load.

  2. Legal Responsibility

    Accessibility is a legal requirement, in some cases. Avoid potential lawsuits by building an accessible website.

  3. Promote Social Responsibility

    Companies can always benefit from being socially responsible. It builds credibility and public trust. Give something back to the community by building an accessible website.

Creating an accessible website can be a complex process, depending on the conformance level you are trying to achieve. Let me help you with this process. I make websites that are:

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