How to add a collapsible section in markdown

1. Example

Click me

Heading

Foo
Bar
- Baz
- Qux

Some Javascript

function logSomething(something) {
  console.log('Something', something);
}

2. Code/Markdown

<details>
  <summary>Click me</summary>
  
  ### Heading
  1. Foo
  2. Bar
     * Baz
     * Qux

  ### Some Javascript
  ```js
  function logSomething(something) {
    console.log('Something', something);
  }
  ```
</details>

3. Tips & Tricks

3.1 Expand by Default

To have a collapsible section expanded by default, simply include the 'open' attribute within the <details> tag:

Hello

World!

<details open>
  <summary>Hello</summary>
  World!
</details>

3.2 Customize Clickable Text

You can modify the appearance of the clickable text by adding styling inside the <summary> tags:

Wow, so fancy

WOW, SO BOLD

<details>
  <summary><i>Wow, so fancy</i></summary>
  <b>WOW, SO BOLD</b>
</details>

3.3 Nested Collapsible Sections

NB: When including headings within collapsible sections, remember to add a new line after the <summary> tag.

Section A

Section A.B

Section A.B.C

Section A.B.C.D

Done!

<details>
<summary>Section A</summary>
<details>
<summary>Section A.B</summary>
<details>
<summary>Section A.B.C</summary>
<details>
<summary>Section A.B.C.D</summary>
  Done!
</details>
</details>
</details>
</details>

Troubleshooting

If certain markdown or styling, such as # My Title, fails to render in the collapsible section, try adding a line break after the </summary> tag.
If your section fails to render, it might be malformed. Consider copying the functional examples provided here and building from there!

marymlucas/markdown-details-collapsible.md