The HTML Details Element (<details>) creates a disclosure widget in which information is visible only when the widget is toggled into an "open" state. A summary or label can be provided using the <summary> element.

A disclosure widget is typically presented onscreen using a small triangle which rotates (or twists) to indicate open/closed status, with a label next to the triangle. If the first child of the <details> element is a <summary>, the contents of the <summary> element are used as the label for the disclosure widget.

Note: The common use of a triangle which rotates or twists around to represent opening or closing the widget is why these are sometimes called "twisties."

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>). This might look like the following:

Screenshot of closed <details> widget. A black left-pointing triangle sits to the right of the text “System Requirements”.

Here we see a standard disclosure widget with the label "System Requirements", in its default closed state. When the user clicks on the widget, or focuses it then presses the space bar, it "twists" open, revealing its contents:

Screenshot of open <details> widget. The triangle now points downward, and a detailed description of what “System Requirements” means is shown.

From there, you can use CSS to style the disclosure widget, and you can programmatically open and close the widget by setting/removing its open attribute.

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.

Note: Unfortunately, at this time there's no built-in way to animate the transition between open and closed.

Fully standards-compliant implementations automatically apply the CSS display: list-item to the <summary> element. You can use this to customize its appearance further. See Customizing the disclosure widget for further details.

Content categories Flow content, sectioning root, interactive content, palpable content.
Permitted content One <summary> element followed by flow content.
Tag omission None, both the starting and ending tag are mandatory.
Permitted parents Any element that accepts flow content.
Permitted ARIA roles None
DOM interface HTMLDetailsElement

Attributes

This element includes the global attributes.

open
This Boolean attribute indicates whether or not the details — that is, the contents of the <details> element — are currently visible. The default, false, means the details are not visible.

Events

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 listen for the toggle event to detect when the widget changes state:

detailsElem.addEventListener("toggle", function(evt) {
  if (detailsElem.open) {
    /* the element was toggled open */
  } else {
    /* the element was toggled closed */
  }
}, false);

Examples

A simple disclosure example

This example shows a <details> element with no provided summary.

<details>
  <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>

In this situation, the browser will use a default summary string (usually "Details"). Here's what your browser does with it:

Providing a summary

This example adds a summary to the above example by using the <summary> element inside <details>, like this:

<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>

The result from this HTML is this:

Creating an open disclosure box

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>

This results in:

Customizing the appearance

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

CSS

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

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

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

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

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

Customizing the disclosure widget

The disclosure triangle itself can be customized, although this is not as broadly supported. There are variations in how browsers support this customization due to experimental implementations as the element was standardized, so we'll have to use multiple approaches for a while.

The <summary> element supports the list-style shorthand property and its longhand properties, such as list-style-type, to change the disclosure triangle to whatever you choose (usually with list-style-image). For example, we can remove the disclosure widget icon by setting list-style: none.

Chrome doesn't support this yet, however, so we also need to use its non-standard ::-webkit-details-marker pseudo-element to customize the appearance in that browser.

CSS

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

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

details > summary::-webkit-details-marker {
  display: none;
}

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

This CSS creates a look similar to a tab interface, where activating the tab expands and opens it to reveal its contents.

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

Specifications

Specification Status Comment
HTML Living Standard
The definition of '<details>' in that specification.
Living Standard  
HTML 5.1
The definition of '<details>' in that specification.
Recommendation Initial definition

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support12 No1492 No156
open12 No149 No156
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support Yes Yes No493146.1 Yes
open4 Yes No49146.1 Yes

1. Under consideration.

2. Before Firefox 57, there was a bug meaning that <details> elements can't be made open by default using the open attribute if they have a CSS animation active on them.

3. There is a bug meaning that <details> elements can't be made open by default using the open attribute if they have a CSS animation active on them.

See also