Highlight.js
JavaScript syntax highlighter with language auto-detection and zero depende...
README
Highlight.js
Highlight.js is a syntax highlighter written in JavaScript. It works in
the browser as well as on the server. It can work with pretty much any
markup, doesn’t depend on any other frameworks, and has automatic language
detection.
Contents
- [Node.js / require](#nodejs--require)
- [ES6 Modules / import](#es6-modules--import)
- License
- Links
Upgrading to Version 11
As always, major releases do contain breaking changes which may require action from users. Please read VERSION_11_UPGRADE.md for a detailed summary of breaking changes and any actions you may need to take.
Support for older versions
Please see SECURITY.md for long-term support information.
Basic Usage
In the Browser
The bare minimum for using highlight.js on a web page is linking to the
library along with one of the themes and calling [highlightAll][1]:
- ``` html
- <link rel="stylesheet" href="/path/to/styles/default.min.css">
- <script src="/path/to/highlight.min.js"></script>
- <script>hljs.highlightAll();</script>
- ```
` tags; it triesto detect the language automatically. If automatic detection doesn’twork for you, or you simply prefer to be explicit, you can specify the language manually in the using the class attribute:
- ``` html
- <pre><code class="language-html">...</code></pre>
- ```
Plaintext Code Blocks
To apply the Highlight.js styling to plaintext without actually highlighting it, use the plaintext language:
- ``` html
- <pre><code class="language-plaintext">...</code></pre>
- ```
Ignoring a Code Block
To skip highlighting of a code block completely, use the nohighlight class:
- ``` html
- <pre><code class="nohighlight">...</code></pre>
- ```
Node.js on the Server
The bare minimum to auto-detect the language and highlight some code.
- ``` js
- // load the library and ALL languages
- hljs = require('highlight.js');
- html = hljs.highlightAuto('<h1>Hello World!</h1>').value
- ```
To load only a "common" subset of popular languages:
- ``` js
- hljs = require('highlight.js/lib/common');
- ```
To highlight code with a specific language, use highlight:
- ``` js
- html = hljs.highlight('<h1>Hello World!</h1>', {language: 'xml'}).value
- ```
See Importing the Library for more examples ofrequire vs import usage, etc. For more information about the result object returned by highlight or highlightAuto refer to the api docs.
Supported Languages
Highlight.js supports over 180 languages in the core library. There are also 3rd partylanguage definitions available to support even more languages. You can find the full list of supported languages in [SUPPORTED_LANGUAGES.md][9].
Custom Usage
If you need a bit more control over the initialization ofHighlight.js, you can use the [highlightElement][3] and [configure][4]functions. This allows you to better control what to highlight and when.
For example, here’s the rough equivalent of calling [highlightAll][1] but doing the work manually instead:
- ``` js
- document.addEventListener('DOMContentLoaded', (event) => {
- document.querySelectorAll('pre code').forEach((el) => {
- hljs.highlightElement(el);
- });
- });
- ```
Please refer to the documentation for [configure][4] options.
Using custom HTML
We strongly recommend `` wrapping for code blocks. It's quitesemantic and "just works" out of the box with zero fiddling. It is possible touse other HTML elements (or combos), but you may need to pay special attention topreserving linebreaks.
Let's say your markup for code blocks uses divs:
- ``` html
- <div class='code'>...</div>
- ```
To highlight such blocks manually:
- ``` js
- // first, find all the div.code blocks
- document.querySelectorAll('div.code').forEach(el => {
- // then highlight each
- hljs.highlightElement(el);
- });
- ```
Without using a tag that preserves linebreaks (like pre) you'll need someadditional CSS to help preserve them. You could also [pre and post-process linebreaks with a plug-in][brPlugin], but we recommend using CSS.
[brPlugin]: https://github.com/highlightjs/highlight.js/issues/2559
To preserve linebreaks inside a div using CSS:
- ```css
- div.code {
- white-space: pre;
- }
- ```
Using with Vue.js
See highlightjs/vue-plugin for a simple Vue plugin that works great with Highlight.js.
An example of vue-plugin in action:
- ``` html
- <div id="app">
-
- <highlightjs autodetect :code="code" />
-
- <highlightjs language='javascript' code="var x = 5;" />
- </div>
- ```
Using Web Workers
You can run highlighting inside a web worker to avoid freezing the browserwindow while dealing with very big chunks of code.
In your main script:
- ``` js
- addEventListener('load', () => {
- const code = document.querySelector('#code');
- const worker = new Worker('worker.js');
- worker.onmessage = (event) => { code.innerHTML = event.data; }
- worker.postMessage(code.textContent);
- });
- ```
In worker.js:
- ``` js
- onmessage = (event) => {
- importScripts('<path>/highlight.min.js');
- const result = self.hljs.highlightAuto(event.data);
- postMessage(result.value);
- };
- ```
Importing the Library
Node.js / require
Requiring the top-level library will load all languages:
- ``` js
- // require the highlight.js library, including all languages
- const hljs = require('./highlight.js');
- const highlightedCode = hljs.highlightAuto('<span>Hello World!</span>').value
- ```
For a smaller footprint, load our common subset of languages (the same set used for our default web build).
- ``` js
- const hljs = require('highlight.js/lib/common');
- ```
For the smallest footprint, load only the languages you need:
- ``` js
- const hljs = require('highlight.js/lib/core');
- hljs.registerLanguage('xml', require('highlight.js/lib/languages/xml'));
- const highlightedCode = hljs.highlight('<span>Hello World!</span>', {language: 'xml'}).value
- ```
ES6 Modules / import
*Note: You can also import directly from fully static URLs, such as our very own pre-builtES6 Module CDN resources. See Fetch via CDN for specific examples.*
The default import will register all languages:
- ``` js
- import hljs from 'highlight.js';
- ```
It is more efficient to import only the library and register the languages you need:
- ``` js
- import hljs from 'highlight.js/lib/core';
- import javascript from 'highlight.js/lib/languages/javascript';
- hljs.registerLanguage('javascript', javascript);
- ```
If your build tool processes CSS imports, you can also import the theme directly as a module:
- ``` js
- import hljs from 'highlight.js';
- import 'highlight.js/styles/github.css';
- ```
Getting the Library
You can get highlight.js as a hosted, or custom-build, browser script oras a server module. Right out of the box the browser script supportsboth AMD and CommonJS, so if you wish you can use RequireJS orBrowserify without having to build from source. The server module alsoworks perfectly fine with Browserify, but there is the option to use abuild specific to browsers rather than something meant for a server.
Do not link to GitHub directly. The library is not supposed to work straightfrom the source, it requires building. If none of the pre-packaged optionswork for you refer to the [building documentation][6].
On Almond. You need to use the optimizer to give the module a name. Forexample:
- ``` sh
- r.js -o name=hljs paths.hljs=/path/to/highlight out=highlight.js
- ```
Fetch via CDN
A prebuilt version of Highlight.js bundled with many common languages is hosted by several popular CDNs.When using Highlight.js via CDN you can use Subresource Integrity for additional security. For detailssee DIGESTS.md.
cdnjs (link)
Common JS
- ``` html
- <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/highlight.js/11.7.0/styles/default.min.css">
- <script src="https://cdnjs.cloudflare.com/ajax/libs/highlight.js/11.7.0/highlight.min.js"></script>
- <script src="https://cdnjs.cloudflare.com/ajax/libs/highlight.js/11.7.0/languages/go.min.js"></script>
- ```
ES6 Modules
- ```` html
- <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/highlight.js/11.7.0/styles/dark.min.css">
- <script type="module">
- import hljs from 'https://cdnjs.cloudflare.com/ajax/libs/highlight.js/11.7.0/es/highlight.min.js';
- // and it's easy to individually load additional languages
- import go from 'https://cdnjs.cloudflare.com/ajax/libs/highlight.js/11.7.0/es/languages/go.min.js';
- hljs.registerLanguage('go', go);
- </script>
- ````
jsdelivr (link)
Common JS
- ``` html
- <link rel="stylesheet" href="https://cdn.jsdelivr.net/gh/highlightjs/cdn-release@11.7.0/build/styles/default.min.css">
- <script src="https://cdn.jsdelivr.net/gh/highlightjs/cdn-release@11.7.0/build/highlight.min.js"></script>
- <script src="https://cdn.jsdelivr.net/gh/highlightjs/cdn-release@11.7.0/build/languages/go.min.js"></script>
- ```
ES6 Modules
- ``` html
- <link rel="stylesheet" href="https://cdn.jsdelivr.net/gh/highlightjs/cdn-release@11.7.0/build/styles/default.min.css">
- <script type="module">
- import hljs from 'https://cdn.jsdelivr.net/gh/highlightjs/cdn-release@11.7.0/build/es/highlight.min.js';
- // and it's easy to individually load additional languages
- import go from 'https://cdn.jsdelivr.net/gh/highlightjs/cdn-release@11.7.0/build/es/languages/go.min.js';
- hljs.registerLanguage('go', go);
- </script>
- ```
unpkg (link)
Common JS
- ``` html
- <link rel="stylesheet" href="https://unpkg.com/@highlightjs/cdn-assets@11.7.0/styles/default.min.css">
- <script src="https://unpkg.com/@highlightjs/cdn-assets@11.7.0/highlight.min.js"></script>
- <script src="https://unpkg.com/@highlightjs/cdn-assets@11.7.0/languages/go.min.js"></script>
- ```
ES6 Modules
- ``` html
- <link rel="stylesheet" href="https://unpkg.com/@highlightjs/cdn-assets@11.7.0/styles/default.min.css">
- <script type="module">
- import hljs from 'https://unpkg.com/@highlightjs/cdn-assets@11.7.0/es/highlight.min.js';
- // and it's easy to individually load & register additional languages
- import go from 'https://unpkg.com/@highlightjs/cdn-assets@11.7.0/es/languages/go.min.js';
- hljs.registerLanguage('go', go);
- </script>
- ```
Note: The CDN-hosted highlight.min.js package doesn't bundle every language. It would bevery large. You can find our list of "common" languages that we bundle by default on our [download page][5].
Download prebuilt CDN assets
You can also download and self-host the same assets we serve up via our own CDNs. We publish those builds to the cdn-release GitHub repository. You can easily pull individual files off the CDN endpoints withcurl, etc; if say you only needed highlight.min.js and a single CSS file.
There is also an npm package @highlightjs/cdn-assets if pulling the assets in vianpm or yarn would be easier for your build process.
Download from our website
The [download page][5] can quickly generate a custom single-file minified bundle including only the languages you desire.
Note: Building from source can produce slightly smaller builds than the website download.
Install via NPM package
Our NPM package including all supported languages can be installed with NPM or Yarn:
- ``` sh
- npm install highlight.js
- # or
- yarn add highlight.js
- ```
Alternatively, you can build the NPM package from source.
Build from Source
The [current source code][10] is always available on GitHub.
- ``` sh
- node tools/build.js -t node
- node tools/build.js -t browser :common
- node tools/build.js -t cdn :common
- ```
See our [building documentation][6] for more information.
Requirements
Highlight.js works on all modern browsers and currently supported Node.js versions. You'll need the following software to contribute to the core library:
- Node.js >= 12.x- npm >= 6.x
License
Highlight.js is released under the BSD License. See our [LICENSE][7] filefor details.
Links
The official website for the library is .
Further in-depth documentation for the API and other topics is at .
A list of the Core Team and contributors can be found in the [CONTRIBUTORS.md][8] file.
[1]: http://highlightjs.readthedocs.io/en/latest/api.html#highlightall[2]: http://highlightjs.readthedocs.io/en/latest/css-classes-reference.html[3]: http://highlightjs.readthedocs.io/en/latest/api.html#highlightelement[4]: http://highlightjs.readthedocs.io/en/latest/api.html#configure[5]: https://highlightjs.org/download/[6]: http://highlightjs.readthedocs.io/en/latest/building-testing.html[7]: https://github.com/highlightjs/highlight.js/blob/main/LICENSE[8]: https://github.com/highlightjs/highlight.js/blob/main/CONTRIBUTORS.md[9]: https://github.com/highlightjs/highlight.js/blob/main/SUPPORTED_LANGUAGES.md[10]: https://github.com/highlightjs/