HTML <details> Tag

The HTML <details> tag represents additional details that the user can view or hide on demand.

It is used with the <summary> tag to provide a legend that can be clicked on to expand/collapse the details as required. If there is not <summary> tag, the browser should display its own summary/legend.

The <details> element accepts "flow content", which means that it accepts most HTML elements that can appear within the <body> of an HTML document.


The <details> tag is written as <details></details> with a <summary> tag inserted between the start and end tag. The expandable/collapsible content follows the <summary> tag (but is also contained between the start and end tags of the <details> element).

Like this:


Basic tag usage

Here, the <details> is used along with the <summary> tag to create expandable content.

Default Legend

If you leave the <summary> tag out, the browser should create its own legend.

Multiple <details> Elements

You can have multiple <details> elements, all expanding and collapsing their own content. This is where the <summary> tag can really come in handy, otherwise you will see a whole bunch of headings that read Details with nothing else to distinguish each one.

The <details> tag can be used to show/hide most elements that appear within an HTML document's <body> element. This includes text, form controls, images, etc.

The following example demonstrates various elements being placed within the <details> element.

Styling the <details> Element

You can use CSS to add styles to the <details> element. Not only that, you can use it to style the element in its various states (i.e. open and closed), as well as the <summary> element depending on the state of the <details> element. In other words, you can specify different styles to use on both the <details> and the <summary> elements based on whether the user has expanded or collapsed the control.

Like this:


Attributes can be added to an HTML element to provide more information about how the element should appear or behave.

The <details> element accepts the following attributes.

openSpecifies whether the details should be open (visible to the user) or closed (hidden from the user).

This is a boolean attribute. If the attribute is present, its value must either be the empty string or a value that is an ASCII case-insensitive match for the attribute's canonical name, with no leading or trailing whitespace (i.e. either open or open="open").

Possible values:

  • [Empty string]
  • open

Global Attributes

The following attributes are standard across all HTML elements. Therefore, you can use these attributes with the <details> tag , as well as with all other HTML tags.

For a full explanation of these attributes, see HTML 5 global attributes.

Event Handlers

Event handler content attributes enable you to invoke a script from within your HTML. The script is invoked when a certain "event" occurs. Each event handler content attribute deals with a different event.

Most event handler content attributes can be used on all HTML elements, but some event handlers have specific rules around when they can be used and which elements they are applicable to.

For more detail, see HTML event handler content attributes.