WCAG Governing Principles
WCAG is built on four governing principles, commonly refer to by the acronym POUR.
- Perceivable;
- Operable;
- Understandable; and
- Robust.
- Perceivable: Any visitor must always be able to understand the intent of the items and content on a web page. Every web element must be able to be described and understood by people with disabilities and assistive technology devices. This means that the front-facing web page must match the programmatic code behind that web page. Web elements must appear in the code in the same order it is intended to be read or understood.
Below are a few examples:- If a web page contains a button, the source code must contain a label that reads "This is a button, and if you click on it, _____ happens."
- If a user clicks on a video, the video must display closed captions or transcripts, so that people who are hearing impaired can read the information that is being spoken in the video.
- If the web page contains a widget, the code must clearly define what the widget does (using ARIA attributes) so the end user understands what the web page is tying to portray.
- Here is an example of programmatic code done incorrectly.
- Operable: Any visitor (including any person with a disability) must be able to operate our website.
- Understandable: Any visitor must be able to understand our content.
- Robust: Any visitor must be able to get the information they need when visiting our website regardless of any alternate technology (e.g. keyboard, screen reader, mobile device) they may be using.
