react.dev/docs/ref-07-special-non-dom-attr...

---
id: special-non-dom-attributes
title: Special Non-DOM Attributes
permalink: docs/special-non-dom-attributes.html
prev: dom-differences.html
next: reconciliation.html
---

Beside [DOM differences](/react/docs/dom-differences.html), React offers some attributes that simply don't exist in DOM.

- `key`: an optional, unique identifier. When your component shuffles around during `render` passes, it might be destroyed and recreated due to the diff algorithm. Assigning it a key that persists makes sure the component stays. See more [here](/react/docs/multiple-components.html#dynamic-children).
- `ref`: see [here](/react/docs/more-about-refs.html).
- `dangerouslySetInnerHTML`: Provides the ability to insert raw HTML, mainly for cooperating with DOM string manipulation libraries. See more [here](/react/tips/dangerously-set-inner-html.html).
docs section for non-dom attributes Also added documentation for `dangerouslySetInnerHTML`. 11 years ago			`---`
			`id: special-non-dom-attributes`
			`title: Special Non-DOM Attributes`
Upgrade to Jekyll 3 Full list of changes is at https://jekyllrb.com/docs/upgrading/2-to-3/. The tl;dr of it is: - Relative permalinks were removed, so all the files in the `docs` subdirectory need their permalink to be prefixed with `docs/` - `post` and `page` types were renamed to `posts` and `pages` respectively - `jekyll-paginate`, `pygments` and `redcarpet` are all now optional, so I needed to explicitly add it to the Gemfile. Jekyll now uses `rouge` rather than `pygments` for syntax highlighting, but rouge does not support highlighting individual lines (`hl_lines`) so we need to continue using Pygments. - Layout metadata (eg. `sectionid`) is now on a `layout` variable rather than `page` Tested the following pages and confirmed that they all work: - "Docs" link (getting started page): http://127.0.0.1:4000/react/docs/getting-started.html - Downloads: http://127.0.0.1:4000/react/downloads.html - Tutorial: http://127.0.0.1:4000/react/docs/tutorial.html - A few pages under the "docs" subdirectory, to confirm they're working properly: - http://127.0.0.1:4000/react/docs/addons.html - http://127.0.0.1:4000/react/docs/why-react.html - http://127.0.0.1:4000/react/docs/create-fragment.html - A few tips: - http://127.0.0.1:4000/react/tips/false-in-jsx.html - http://127.0.0.1:4000/react/tips/style-props-value-px.html - Non-English versions of the page: - http://127.0.0.1:4000/react/docs/getting-started-it-IT.html - http://127.0.0.1:4000/react/docs/getting-started-ja-JP.html 9 years ago			`permalink: docs/special-non-dom-attributes.html`
docs section for non-dom attributes Also added documentation for `dangerouslySetInnerHTML`. 11 years ago			`prev: dom-differences.html`
Document the Diff algorithm We often refer to it but never did actually explain it. 11 years ago			`next: reconciliation.html`
docs section for non-dom attributes Also added documentation for `dangerouslySetInnerHTML`. 11 years ago			`---`

			`Beside [DOM differences](/react/docs/dom-differences.html), React offers some attributes that simply don't exist in DOM.`

			- `key`: an optional, unique identifier. When your component shuffles around during `render` passes, it might be destroyed and recreated due to the diff algorithm. Assigning it a key that persists makes sure the component stays. See more [here](/react/docs/multiple-components.html#dynamic-children).
			- `ref`: see [here](/react/docs/more-about-refs.html).
Document justification for dangerouslySetInnerHTML, fixes #2256 Conflicts: docs/_data/nav_tips.yml docs/tips/17-children-undefined.md 10 years ago			- `dangerouslySetInnerHTML`: Provides the ability to insert raw HTML, mainly for cooperating with DOM string manipulation libraries. See more [here](/react/tips/dangerously-set-inner-html.html).