The World Wide Web has become a universal part of everyday life. Whether at work, school, or home, many tasks are now difficult to complete without access to the internet. Registering for university, applying for a job, filing tax returns, or booking travel are just a few examples of tasks we complete using the Internet.

Because of the convenience and ease of accessing information, people from all walks of life are now connected. Many have varying needs and abilities and may obtain and interpret information using different senses and techniques. Consider the following examples:

• People who are blind or have significant vision loss and cannot see a screen.
• People who are deaf or have significant hearing loss and have difficulty hearing audio content.
• People who have difficulty controlling their hands and arms when using a mouse, keyboard, or touch screen.
• People with developmental or learning disabilities who may struggle to understand the complex content.
• The elderly, who in addition to being increasingly likely to fall into other groups, may not have adapted to technology as well as the younger generation.

Each group of people on this list have a unique way of accessing the Internet in a format they can understand. Individuals who are blind or visually impaired may use screen reading software that will translate the contents of a screen into synthesized speech or Braille. There is also the option of using screen magnification programs to enlarge content, with or without speech as a backup. People with motor disabilities who cannot operate a physical device might use dictation software to input text and perform actions based on what the user speaks.

A Web accessibility strategy needs to take all assistive technologies and user limitations into account to be effective. It must incorporate the content following four broad guidelines: Perceived content, operable content, understandable content and robust content.

Perceivable content is content that can be understood using sight, touch, or hearing. The user is not limited in how they can read or interact with it. The text is perceivable because it can be read using multiple senses depending on the employment of assistive technology. Pictures of text, audio without video, or transcripts, are not perceivable to all users because they are compatible with one sense and impossible to interpret if that particular sense is limited or non-functional.

Operable content refers to content that can interact with both a keyboard and a mouse. Most standard web page elements are operable because they are designed to work with both a keyboard and a mouse. Custom web page controls with manually created mouse click actions are not operable because a keyboard is unable to trigger the same process.

Understandable content is user-friendly and easy to comprehend. A site with consistent navigation, or one that incorporates forms with clear instructions, is comprehensible. A website using a form that has no instructions would not be intelligible to the disabled user.

Robust content can be loaded on many browsers and devices, and operated using assistive technologies. Content that is compliant with website operating standards is robust, as devices and programs are designed to be able to understand them. Custom controls that are not standard tend to be less powerful and limit the number of devices that can be used to browse a website.

In a society where Internet access is essential for equal participation and opportunity, it is vital that we design websites with accessibility in mind. An accessible Internet allows people to share ideas and engage in society regardless of disability, hardship, or circumstance. As we continue to explore accessibility, the four guidelines of perceivable, operable, understandable and robust content will be analyzed in more detail, providing tips and examples for making a website accessible to all.