The Details disclosure element

The <details> HTML element creates an accordion-like element that the user can toggle open and close.

The W3C HTML specification describes the element:

The details element represents a disclosure widget from which the user can obtain additional information or controls.

Usage

<details>
  <summary>Show/Hide</summary>
  <p>Today I learnt about the `details` element</p>
</details>

The open attribute is a boolean that can be used to indicate if the content is visible or not.

<details open="true">
  <summary>Show/Hide</summary>
  <p>Today I learnt about the `details` element</p>
</details>