Use the elements of HTML to create collapsible areas without JavaScript or CSS. 1.
is a click title, the default content is hidden, click to toggle display. 2. Add the open attribute to expand the content by default. 3. Use CSS to customize styles, such as borders, inner margins and background colors. 4. The default triangle arrow can be hidden through list-style: none or ::-webkit-details-marker. 5. Commonly used in FAQ, additional information, setting options and other scenarios. The solution is semantics, accessible and friendly, and has good browser support. It only requires pure HTML to achieve full functionality.
Creating a collapsed section in HTML is simple and doesn't require any JavaScript or CSS if you use the <details></details>
and <summary></summary>
elements. These are native HTML5 tags designed exactly for this purpose.

How <details></details>
and <summary></summary>
Work
- The
<details></details>
element creates a disclosure widget (a collapse container). - The
<summary></summary>
element acts as the clickable label or heading for the collapse section. - By default, the content inside
<details></details>
is hidden. When the user clicks the<summary></summary>
, the content toggles visibility.
Basic Syntax
<details> <summary>Click to expand</summary> <p>This is the hidden content that appears when expanded.</p> </details>
When rendered:
- You'll see a small triangle (?) next to "Click to expand".
- Clicking it expands the section and reveals the paragraph.
- Clicking again collapses it.
Key Features and Tips
1. Default Open State
Use the open
attribute to make the section expanded by default:

<details open> <summary>Already expanded</summary> <p>This content is visible right away.</p> </details>
2. Styling with CSS (Optional)
You can customize the appearance:
details { margin-bottom: 1rem; border: 1px solid #ccc; border-radius: 4px; padding: 0.5rem; } summary { font-weight: bold; cursor: pointer; } details[open] { background-color: #f9f9f9; }
3. Hide the Default Triangle (Optional)
If you want to remove the arrow icon:

summary { list-style: none; /* Removes the default arrow */ }
Or use ::-webkit-details-marker
for more control (WebKit/Blink browsers):
summary::-webkit-details-marker { display: none; }
Common Use Cases
- FAQ sections
- Show/hide additional info (eg, terms and conditions)
- Organizing settings or filters
- Technical documentation toggles
Notes
- Accessibility: These elements are screen-reader friendly and keyboard-navigable by default.
- Browser Support: Excellent — supported in all modern browsers (Chrome, Firefox, Safari, Edge).
- No JavaScript Needed: It works out of the box.
That's it! You've got a fully functional collapse section with just HTML. No frameworks, no scripts — just clean, semantic markup.
The above is the detailed content of How to create a collapsible section with and ?. For more information, please follow other related articles on the PHP Chinese website!

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