<details>: The Details disclosure element

A <details> widget can be in one of two states. The default closed state displays only the triangle and the label inside <summary> (or a user agent-defined default string if no <summary>).

When the user clicks on the widget or focuses it then presses the space bar, it "twists" open, revealing its contents. The common use of a triangle which rotates or twists around to represent opening or closing the widget is why these are sometimes called "twisty".

You can use CSS to style the disclosure widget, and you can programmatically open and close the widget by setting/removing its open attribute. Unfortunately, at this time, there's no built-in way to animate the transition between open and closed.

By default when closed, the widget is only tall enough to display the disclosure triangle and summary. When open, it expands to display the details contained within.

Fully standards-compliant implementations automatically apply the CSS display: list-item to the <summary> element. You can use this or the ::marker pseudo-element to customize the disclosure widget.

This element includes the global attributes.

open

This Boolean attribute indicates whether the details — that is, the contents of the <details> element — are currently visible. The details are shown when this attribute exists, or hidden when this attribute is absent. By default this attribute is absent which means the details are not visible.

Note: You have to remove this attribute entirely to make the details hidden. open="false" makes the details visible because this attribute is Boolean.

name

This attribute enables multiple <details> elements to be connected, with only one open at a time. This allows developers to easily create UI features such as accordions without scripting.

The name attribute specifies a group name — give multiple <details> elements the same name value to group them. Only one of the grouped <details> elements can be open at a time — opening one will cause another to close. If multiple grouped <details> elements are given the open attribute, only the first one in the source order will be rendered open.

Note: <details> elements don't have to be adjacent to one another in the source to be part of the same group.

In addition to the usual events supported by HTML elements, the <details> element supports the toggle event, which is dispatched to the <details> element whenever its state changes between open and closed. It is sent after the state is changed, although if the state changes multiple times before the browser can dispatch the event, the events are coalesced so that only one is sent.

You can use an event listener for the toggle event to detect when the widget changes state:

details.addEventListener("toggle", (event) => {
  if (details.open) {
    /* the element was toggled open */
  } else {
    /* the element was toggled closed */
  }
});

This example shows a simple <details> element with a <summary>.

<details>
  <summary>System Requirements</summary>
  <p>
    Requires a computer running an operating system. The computer must have some
    memory and ideally some kind of long-term storage. An input device as well
    as some form of output device is recommended.
  </p>
</details>

Result

To start the <details> box in its open state, add the Boolean open attribute:

<details open>
  <summary>System Requirements</summary>
  <p>
    Requires a computer running an operating system. The computer must have some
    memory and ideally some kind of long-term storage. An input device as well
    as some form of output device is recommended.
  </p>
</details>

Result

We include several <details> boxes, all with the same name so only one can be open at a time:

<details name="reqs">
  <summary>Graduation Requirements</summary>
  <p>
    Requires 40 credits, including a passing grade in health, geography,
    history, economics, and wood shop.
  </p>
</details>
<details name="reqs">
  <summary>System Requirements</summary>
  <p>
    Requires a computer running an operating system. The computer must have some
    memory and ideally some kind of long-term storage. An input device as well
    as some form of output device is recommended.
  </p>
</details>
<details name="reqs">
  <summary>Job Requirements</summary>
  <p>
    Requires knowledge of HTML, CSS, JavaScript, accessibility, web performance,
    privacy, security, and internationalization, as well as a dislike of
    broccoli.
  </p>
</details>

Result

Try opening all the disclosure widgets. When you open one, all the others automatically close.

Now let's apply some CSS to customize the appearance of the disclosure box.

CSS

details {
  font:
    16px "Open Sans",
    Calibri,
    sans-serif;
  width: 620px;
}

details > summary {
  padding: 2px 6px;
  width: 15em;
  background-color: #ddd;
  border: none;
  box-shadow: 3px 3px 4px black;
  cursor: pointer;
}

details > p {
  border-radius: 0 0 10px 10px;
  background-color: #ddd;
  padding: 2px 6px;
  margin: 0;
  box-shadow: 3px 3px 4px black;
}

details[open] > summary {
  background-color: #ccf;
}

This CSS creates a look similar to a tabbed interface, where clicking the tab opens it to reveal its contents.

The selector details[open] can be used to style the element which is open.

HTML

<details>
  <summary>System Requirements</summary>
  <p>
    Requires a computer running an operating system. The computer must have some
    memory and ideally some kind of long-term storage. An input device as well
    as some form of output device is recommended.
  </p>
</details>

Result

See the <summary> page for an example of customizing the disclosure widget.

• <summary>