Learn how to build an expandable and collapsible component using the native HTML details tag

The article explains how to create an expandable and collapsible component using the native HTML details tag, which is natively accessible without the need for JavaScript or WAI-ARIA. To ensure accessibility, certain requirements must be met, such as collapsing and expanding the disclosure element with the Enter or Space keys, moving focus to the next interactive element with Tab, and moving focus to the previous interactive element with Shift + Tab.

The screen reader must also announce the state of the element and its accessible name. The article highlights the anatomy of the details tag, which includes a wrapper element, a summary element acting as the control to expand or collapse the content, and the content itself. The details tag automatically detects the content as a child element, and the open attribute can be used to indicate whether the details content is expanded or collapsed.

The article also provides CSS strategies to style the disclosure component, such as hiding the native disclosure icon by adding display: flex to the summary selector and adding an aria-hidden attribute to the summary element. Additionally, the article mentions the new ::details-content pseudo-selector introduced in CSS, which eliminates the need for a non-semantic div element to style the wrapper of the content and handles transitions between collapsed and expanded states.

The article concludes by emphasizing the importance of semantic structure and accessibility considerations when implementing an expandable and collapsible component using the native HTML details tag.