# open attribute

A Boolean attribute that makes a details element expanded or a dialog displayed.

## What is **`open` attribute**?

**`open` attribute** — A Boolean attribute that makes a details element expanded or a dialog displayed.

Level: Journeyman · [More HTML terms at this level](https://www.ask-codey.com/glossary/subjects/html/journeyman)

Updated: September 27, 2026

Source: https://www.ask-codey.com/glossary/open-attribute