It’s a pretty useful element that handles accordion / collapsed text natively!

You wrap a details element around any block of HTML content. The browser will collapse that block of text until a user opens the details block.

Once a user opens a details block, they’ll be able to read all that hidden content!

If you want the details block open by default, include the open attribute on the opening tag:

...

That’s pretty manageable too! Use the summary element.

Put a summary at the beginning of your details element and Boom! – you’ve got a custom title for your details block.

No worries if you don’t add a summary. The browser will put the word “Details” in there for you. (After all, users need something to click!)

Yes, you’re covered there too! Style the details element however you like. Give it a border, some padding, whatever.

The summary element is where the ▸ marker lives. If you want to get rid of that, there is a prefixed pseudo-element selector ::-webkit-details-marker: set that to display: none for WebKit browsers. In Firefox, it’s much simpler: set the summary to display: block or flex (anything but the native display: list-item) and you’ll get rid of the ▸ for you.

Once again, details has got your back! When a details block is open, it has the open attribute that I mentioned earlier. To style it (or its children) based on its state, use details[open] { }.

Note: there’s no closed attribute: styles you apply by “default” will be used on the closed state.

Open the JS panel on this pen. Clean as a whistle! This is handled totally by the browser.

Sorry to disappoint you. Since these are native HTML elements, they provide useful semantic information to screen readers.

Screen readers will typically read the summary for a collapsed details block (and communicate that it’s collapsed). They’ll also provide an interactive hook for users to open the details block. If the details is already expanded, they’ll read the whole content.

I don’t rely on assistive tech to read the web, so I’m probably not aware of some limitations or drawbacks to using details and summary, but I suspect their AX is at least as good as (if not better than) most JavaScript-dependent accordion solutions.

You bet! Here are some great resources on details & summary:

• MDN: details, summary
• HTML5Doctor
• Scott O’Hara
• Treehouse Blog
• Envato Tuts+
• caniuse table for details

Yeah, sorry. Here’s some bad news. IE, Edge, and Opera Mini don’t currently support details/summary with native open/close behavior (check out caniuse data for details).

These browsers will show all your details elements expanded. That’s not the worst though: it’s a bit of progressive enhancement: if the browser doesn’t support the native UI behavior, the content will still be visible to users.

It’s unlikey IE11 will be getting any updates on this front, but there’s hope for Edge! If this is important to you, please cast a vote a vote for Edge to support details/summary. (Or just wait for Edge to use Chromium, I guess. 😕)

If you do need to have open/close behavior in IE11 (or any other non-supporting browser), you’ll probably need a polyfill. This Smashing Magazine details polyfill tutorial looks like a good place to start.