The World Wide Web Consortium (W3C) is an international organization finding consensus on the technical standards of the web. They produce the Web Content Accessibility Guidelines (WCAG), which is widely regarded as the standards for an accessible website. The tenants of WCAG are that a site must be perceivable, operable, understandable, and robust.
Perceivable
WebAIM has a color contrast checker (pictured above) to determine if your color choice is accessible to people with low vision according to WCAG.
Make sure all information can be understood through multiple modes. This includes adding alt text to images, providing captions, and that important information is visually distinct from the background.
Operable
Pictured above is a mouthstick, which allows users to operate a keyboard, but can be tedious to do too many keystrokes. For a site to be operable, it needs to be able to be used easily with different accessible hardware, like keyboard controls. A site also needs to have clear navigation and to give plenty of time to users for completing tasks.
Understandable
Google Forms uses this navigation, where the steps of the process are laid out, allowing a user to keep track of their progress.
An understandable website provides help for users and is specific when describing errors. A website that is confusing or unpredictable is inaccessible.
Robust
WebAIM surveys screen reader users every few years to find out their preferences in using the internet. In 2017, 88% of users reported using a screen reader on a mobile device.
To be sure that the website will interact with current and future assistive technologies, the code must follow best practices. Elements must be nested properly, and all details like end tags should be in place.
Other Resources
WebAIM is an educational resource dedicated to web accessibility with detailed information on the technical details that make a website accessible.
The A11y Project provides up-to-date widgets and patterns that anyone can use to ensure their site functions properly. The BreadCrumb navigation on this site is from The A11y Project.
8/8