Accessibility tree (a text map of a page's structure)
Japanese アクセシビリティツリー
The accessibility tree is the information a browser builds from a web page, listing each button, link and input field with its name, role and state. Screen readers and AI agents use it to understand the page.
After a browser reads a web page's HTML, it builds a separate list that sums up each part, such as a button, a link or an input field: what it is called (its name), what kind of thing it is (its role) and what state it is in right now. That list is the accessibility tree. Like a braille floor map in a building, it leaves out the looks and keeps only what is where and what you can do with it. Screen readers, which read the screen aloud, rely on this list, and AI agents now use it to understand pages too.
Watch out A part that only looks like a button may not show up as a button in the accessibility tree. Use real button and a elements, and connect each input field to a label. In Chrome DevTools, open the Accessibility tab in the Elements panel to see the accessibility tree of your own pages.
Source: Accessibility tree - Glossary | MDN · Build agent-friendly websites · A developer toolkit to make your website agent-ready · Accessibility features reference (checked 2026-10-26)