HTML <summary> Tag

The HTML <summary> tag specifies a summary/legend that can be used in conjunction with the <details> tag. This summary/legend can be clicked on to expand/collapse the details as required.

Although the <summary> tag is not mandatory, it is useful when working with multiple <details> elements, because each <summary> can provide an informative legend that distinguishes each <details> element from the others.


The <summary> tag is written as <summary></summary> with the summary/legend inserted between the start and end tags.

The <summary> element must be the first child of a <details> tag. The expandable/collapsible content directly follows the <summary> tag (but is also contained within the <details> element).

Like this:


Basic tag usage

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

Default Legend

The <summary> is not mandatory when using the <details> tag. If you leave the <summary> tag out, the browser should create its own legend (however, this is not ideal if you have multiple <details> elements).

Multiple <summary> 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.

Styling the <summary> Element

You can use CSS to add styles to the <summary> element. Not only that, you can use it to style the element while the <details> element is in its various states (i.e. open and closed). In other words, you can specify different styles to use on both the <summary> and the <details> 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 <summary> element accepts the following attributes.


Global Attributes

The following attributes are standard across all HTML elements. Therefore, you can use these attributes with the <summary> 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.