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.

There are 3 kinds of attributes that you can add to your HTML tags: Element-specific, global, and event handler content attributes.

The <details> element accepts the following attributes.

Element-Specific Attributes

This table shows the attributes that are specific to the <details> tag/element.

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 HTML5 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 Handler Content Attributes

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.

Below are the standard HTML5 event handler content attributes.

Again, you can use any of these with the <details> element, as well as any other HTML5 element.

For a full explanation of these attributes, see HTML 5 event handler content attributes.

Differences Between HTML 4 & HTML 5

The <details> element was not part of HTML 4 and earlier specifications.

The <details> tag was also not introduced as part of the HTML5 specification. It was introduced in the HTML 5.1 specification, as well as the WHATWG HTML Living Standard.

For more detail on the <details> element, see HTML5 <details> Tag. Also check out the links to the official specifications below.


Here's a template for the <details> tag with all available attributes for the tag (based on HTML5). These are grouped into attribute types, each type separated by a space. In many cases, you will probably only need one or two (if any) attributes. Simply remove the attributes you don't need.

For more information on attributes for this tag, see HTML5 <details> Tag.

Tag Details

For more details about the <details> tag, see HTML5 <details> Tag.


Here are the official specifications for the <details> element.

What's the Difference?

W3C creates "snapshot" specifications that don't change once defined. So the HTML5 specification won't change once it becomes an official recommendation. WHATWG on the other hand, develops a "living standard" that is updated on a regular basis. In general, you will probably find that the HTML living standard will be more closely aligned to the current W3C draft than to the HTML5 specification.