1 | # Highlight.js
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2 |
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3 | [![latest version](https://badgen.net/npm/v/highlight.js?label=latest)](https://www.npmjs.com/package/highlight.js)
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4 | [![license](https://badgen.net/github/license/highlightjs/highlight.js?color=cyan)](https://github.com/highlightjs/highlight.js/blob/main/LICENSE)
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5 | [![install size](https://badgen.net/packagephobia/install/highlight.js?label=npm+install)](https://packagephobia.now.sh/result?p=highlight.js)
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6 | ![minified](https://img.shields.io/github/size/highlightjs/cdn-release/build/highlight.min.js?label=minified)
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7 | [![NPM downloads weekly](https://badgen.net/npm/dw/highlight.js?label=npm+downloads&color=purple)](https://www.npmjs.com/package/highlight.js)
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8 | [![jsDelivr CDN downloads](https://badgen.net/jsdelivr/hits/gh/highlightjs/cdn-release?label=jsDelivr+CDN&color=purple)](https://www.jsdelivr.com/package/gh/highlightjs/cdn-release)
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9 |
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10 | [![ci status](https://badgen.net/github/checks/highlightjs/highlight.js/main?label=build)](https://github.com/highlightjs/highlight.js/actions/workflows/tests.js.yml)
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11 | [![CodeQL](https://github.com/highlightjs/highlight.js/workflows/CodeQL/badge.svg)](https://github.com/highlightjs/highlight.js/actions/workflows/github-code-scanning/codeql)
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12 | [![vulnerabilities](https://badgen.net/snyk/highlightjs/highlight.js)](https://snyk.io/test/github/highlightjs/highlight.js?targetFile=package.json)
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13 |
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14 | [![discord](https://badgen.net/badge/icon/discord?icon=discord&label&color=pink)](https://discord.gg/M24EbU7ja9)
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15 | [![open issues](https://badgen.net/github/open-issues/highlightjs/highlight.js?label=issues)](https://github.com/highlightjs/highlight.js/issues)
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16 | [![help welcome issues](https://badgen.net/github/label-issues/highlightjs/highlight.js/help%20welcome/open)](https://github.com/highlightjs/highlight.js/issues?q=is%3Aopen+is%3Aissue+label%3A%22help+welcome%22)
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17 | [![good first issue](https://badgen.net/github/label-issues/highlightjs/highlight.js/good%20first%20issue/open)](https://github.com/highlightjs/highlight.js/issues?q=is%3Aopen+is%3Aissue+label%3A%22good+first+issue%22)
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18 |
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19 |
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20 |
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21 |
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22 |
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23 |
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24 |
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25 |
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26 | Highlight.js is a syntax highlighter written in JavaScript. It works in
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27 | the browser as well as on the server. It can work with pretty much any
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28 | markup, doesn’t depend on any other frameworks, and has automatic language
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29 | detection.
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30 |
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31 | **Contents**
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32 |
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33 | - [Basic Usage](#basic-usage)
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34 | - [In the Browser](#in-the-browser)
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35 | - [Plaintext Code Blocks](#plaintext-code-blocks)
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36 | - [Ignoring a Code Block](#ignoring-a-code-block)
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37 | - [Node.js on the Server](#nodejs-on-the-server)
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38 | - [Supported Languages](#supported-languages)
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39 | - [Custom Usage](#custom-usage)
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40 | - [Using custom HTML](#using-custom-html)
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41 | - [Using with Vue.js](#using-with-vuejs)
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42 | - [Using Web Workers](#using-web-workers)
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43 | - [Importing the Library](#importing-the-library)
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44 | - [Node.js / `require`](#nodejs--require)
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45 | - [ES6 Modules / `import`](#es6-modules--import)
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46 | - [Getting the Library](#getting-the-library)
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47 | - [Fetch via CDN](#fetch-via-cdn)
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48 | - [cdnjs (link)](#cdnjs-link)
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49 | - [jsdelivr (link)](#jsdelivr-link)
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50 | - [unpkg (link)](#unpkg-link)
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51 | - [Download prebuilt CDN assets](#download-prebuilt-cdn-assets)
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52 | - [Download from our website](#download-from-our-website)
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53 | - [Install via NPM package](#install-via-npm-package)
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54 | - [Build from Source](#build-from-source)
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55 | - [Requirements](#requirements)
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56 | - [License](#license)
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57 | - [Links](#links)
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58 |
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59 | ---
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60 |
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61 | #### Upgrading to Version 11
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62 |
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63 | As always, major releases do contain breaking changes which may require action from users. Please read [VERSION_11_UPGRADE.md](https://github.com/highlightjs/highlight.js/blob/main/VERSION_11_UPGRADE.md) for a detailed summary of breaking changes and any actions you may need to take.
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64 |
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65 |
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66 | #### Support for older versions <!-- omit in toc -->
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67 |
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68 | Please see [SECURITY.md](https://github.com/highlightjs/highlight.js/blob/main/SECURITY.md) for long-term support information.
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69 |
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70 | ---
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71 |
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72 | ## Basic Usage
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73 | ### In the Browser
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74 |
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75 | The bare minimum for using highlight.js on a web page is linking to the
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76 | library along with one of the themes and calling [`highlightAll`][1]:
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77 |
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78 | ```html
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79 | <link rel="stylesheet" href="/path/to/styles/default.min.css">
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80 | <script src="/path/to/highlight.min.js"></script>
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81 | <script>hljs.highlightAll();</script>
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82 | ```
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83 |
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84 | This will find and highlight code inside of `<pre><code>` tags; it tries
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85 | to detect the language automatically. If automatic detection doesn’t
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86 | work for you, or you simply prefer to be explicit, you can specify the language manually by using the `class` attribute:
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87 |
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88 |
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89 | ```html
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90 | <pre><code class="language-html">...</code></pre>
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91 | ```
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92 |
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93 | #### Plaintext Code Blocks
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94 |
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95 | To apply the Highlight.js styling to plaintext without actually highlighting it, use the `plaintext` language:
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96 |
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97 | ```html
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98 | <pre><code class="language-plaintext">...</code></pre>
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99 | ```
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100 |
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101 | #### Ignoring a Code Block
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102 |
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103 | To skip highlighting of a code block completely, use the `nohighlight` class:
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104 |
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105 | ```html
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106 | <pre><code class="nohighlight">...</code></pre>
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107 | ```
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108 |
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109 | ### Node.js on the Server
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110 |
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111 | The bare minimum to auto-detect the language and highlight some code.
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112 |
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113 | ```js
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114 | // load the library and ALL languages
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115 | hljs = require('highlight.js');
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116 | html = hljs.highlightAuto('<h1>Hello World!</h1>').value
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117 | ```
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118 |
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119 | To load only a "common" subset of popular languages:
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120 |
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121 | ```js
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122 | hljs = require('highlight.js/lib/common');
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123 | ```
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124 |
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125 | To highlight code with a specific language, use `highlight`:
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126 |
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127 | ```js
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128 | html = hljs.highlight('<h1>Hello World!</h1>', {language: 'xml'}).value
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129 | ```
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130 |
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131 | See [Importing the Library](#importing-the-library) for more examples of `require` vs `import` usage, etc. For more information about the result object returned by `highlight` or `highlightAuto` refer to the [api docs](https://highlightjs.readthedocs.io/en/latest/api.html).
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132 |
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133 |
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134 |
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135 | ## Supported Languages
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136 |
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137 | Highlight.js supports over 180 languages in the core library. There are also 3rd party
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138 | language definitions available to support even more languages. You can find the full list of supported languages in [SUPPORTED_LANGUAGES.md][9].
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139 |
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140 | ## Custom Usage
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141 |
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142 | If you need a bit more control over the initialization of
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143 | Highlight.js, you can use the [`highlightElement`][3] and [`configure`][4]
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144 | functions. This allows you to better control *what* to highlight and *when*.
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145 |
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146 | For example, here’s the rough equivalent of calling [`highlightAll`][1] but doing the work manually instead:
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147 |
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148 | ```js
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149 | document.addEventListener('DOMContentLoaded', (event) => {
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150 | document.querySelectorAll('pre code').forEach((el) => {
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151 | hljs.highlightElement(el);
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152 | });
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153 | });
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154 | ```
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155 |
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156 | Please refer to the documentation for [`configure`][4] options.
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157 |
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158 |
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159 | ### Using custom HTML
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160 |
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161 | We strongly recommend `<pre><code>` wrapping for code blocks. It's quite
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162 | semantic and "just works" out of the box with zero fiddling. It is possible to
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163 | use other HTML elements (or combos), but you may need to pay special attention to
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164 | preserving linebreaks.
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165 |
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166 | Let's say your markup for code blocks uses divs:
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167 |
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168 | ```html
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169 | <div class='code'>...</div>
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170 | ```
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171 |
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172 | To highlight such blocks manually:
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173 |
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174 | ```js
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175 | // first, find all the div.code blocks
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176 | document.querySelectorAll('div.code').forEach(el => {
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177 | // then highlight each
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178 | hljs.highlightElement(el);
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179 | });
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180 | ```
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181 |
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182 | Without using a tag that preserves linebreaks (like `pre`) you'll need some
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183 | additional CSS to help preserve them. You could also [pre and post-process line
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184 | breaks with a plug-in][brPlugin], but *we recommend using CSS*.
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185 |
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186 | [brPlugin]: https://github.com/highlightjs/highlight.js/issues/2559
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187 |
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188 | To preserve linebreaks inside a `div` using CSS:
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189 |
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190 | ```css
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191 | div.code {
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192 | white-space: pre;
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193 | }
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194 | ```
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195 |
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196 |
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197 | ### Using with Vue.js
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198 |
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199 | See [highlightjs/vue-plugin](https://github.com/highlightjs/vue-plugin) for a simple Vue plugin that works great with Highlight.js.
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200 |
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201 | An example of `vue-plugin` in action:
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202 |
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203 | ```html
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204 | <div id="app">
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205 | <!-- bind to a data property named `code` -->
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206 | <highlightjs autodetect :code="code" />
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207 | <!-- or literal code works as well -->
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208 | <highlightjs language='javascript' code="var x = 5;" />
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209 | </div>
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210 | ```
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211 |
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212 | ### Using Web Workers
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213 |
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214 | You can run highlighting inside a web worker to avoid freezing the browser
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215 | window while dealing with very big chunks of code.
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216 |
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217 | In your main script:
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218 |
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219 | ```js
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220 | addEventListener('load', () => {
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221 | const code = document.querySelector('#code');
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222 | const worker = new Worker('worker.js');
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223 | worker.onmessage = (event) => { code.innerHTML = event.data; }
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224 | worker.postMessage(code.textContent);
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225 | });
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226 | ```
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227 |
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228 | In worker.js:
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229 |
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230 | ```js
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231 | onmessage = (event) => {
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232 | importScripts('<path>/highlight.min.js');
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233 | const result = self.hljs.highlightAuto(event.data);
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234 | postMessage(result.value);
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235 | };
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236 | ```
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237 |
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238 | ## Importing the Library
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239 |
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240 | First, you'll likely be installing the library via `npm` or `yarn` -- see [Getting the Library](#getting-the-library).
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241 |
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242 |
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243 | ### Node.js / `require`
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244 |
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245 | Requiring the top-level library will load all languages:
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246 |
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247 | ```js
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248 | // require the highlight.js library, including all languages
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249 | const hljs = require('./highlight.js');
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250 | const highlightedCode = hljs.highlightAuto('<span>Hello World!</span>').value
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251 | ```
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252 |
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253 | For a smaller footprint, load our common subset of languages (the same set used for our default web build).
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254 |
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255 | ```js
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256 | const hljs = require('highlight.js/lib/common');
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257 | ```
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258 |
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259 | For the smallest footprint, load only the languages you need:
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260 |
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261 | ```js
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262 | const hljs = require('highlight.js/lib/core');
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263 | hljs.registerLanguage('xml', require('highlight.js/lib/languages/xml'));
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264 |
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265 | const highlightedCode = hljs.highlight('<span>Hello World!</span>', {language: 'xml'}).value
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266 | ```
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267 |
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268 |
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269 | ### ES6 Modules / `import`
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270 |
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271 | *Note: You can also import directly from fully static URLs, such as our very own pre-built
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272 | ES6 Module CDN resources. See [Fetch via CDN](#fetch-via-cdn) for specific examples.*
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273 |
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274 | The default import will register all languages:
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275 |
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276 | ```js
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277 | import hljs from 'highlight.js';
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278 | ```
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279 |
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280 | It is more efficient to import only the library and register the languages you need:
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281 |
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282 | ```js
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283 | import hljs from 'highlight.js/lib/core';
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284 | import javascript from 'highlight.js/lib/languages/javascript';
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285 | hljs.registerLanguage('javascript', javascript);
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286 | ```
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287 |
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288 | If your build tool processes CSS imports, you can also import the theme directly as a module:
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289 |
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290 | ```js
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291 | import hljs from 'highlight.js';
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292 | import 'highlight.js/styles/github.css';
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293 | ```
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294 |
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295 |
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296 | ## Getting the Library
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297 |
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298 | You can get highlight.js as a hosted, or custom-build, browser script or
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299 | as a server module. Right out of the box the browser script supports
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300 | both AMD and CommonJS, so if you wish you can use RequireJS or
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301 | Browserify without having to build from source. The server module also
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302 | works perfectly fine with Browserify, but there is the option to use a
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303 | build specific to browsers rather than something meant for a server.
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304 |
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305 |
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306 | **Do not link to GitHub directly.** The library is not supposed to work straight
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307 | from the source, it requires building. If none of the pre-packaged options
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308 | work for you refer to the [building documentation][6].
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309 |
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310 | **On Almond.** You need to use the optimizer to give the module a name. For
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311 | example:
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312 |
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313 | ```bash
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314 | r.js -o name=hljs paths.hljs=/path/to/highlight out=highlight.js
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315 | ```
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316 |
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317 | ### Fetch via CDN
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318 |
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319 | A prebuilt version of Highlight.js bundled with many common languages is hosted by several popular CDNs.
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320 | When using Highlight.js via CDN you can use Subresource Integrity for additional security. For details
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321 | see [DIGESTS.md](https://github.com/highlightjs/cdn-release/blob/main/DIGESTS.md).
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322 |
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323 | #### cdnjs ([link](https://cdnjs.com/libraries/highlight.js))
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324 |
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325 | ##### Common JS <!-- omit in toc -->
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326 |
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327 | ```html
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328 | <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/highlight.js/11.9.0/styles/default.min.css">
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329 | <script src="https://cdnjs.cloudflare.com/ajax/libs/highlight.js/11.9.0/highlight.min.js"></script>
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330 | <!-- and it's easy to individually load additional languages -->
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331 | <script src="https://cdnjs.cloudflare.com/ajax/libs/highlight.js/11.9.0/languages/go.min.js"></script>
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332 | ```
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333 |
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334 | ##### ES6 Modules <!-- omit in toc -->
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335 |
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336 | ````html
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337 | <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/highlight.js/11.9.0/styles/dark.min.css">
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338 | <script type="module">
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339 | import hljs from 'https://cdnjs.cloudflare.com/ajax/libs/highlight.js/11.9.0/es/highlight.min.js';
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340 | // and it's easy to individually load additional languages
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341 | import go from 'https://cdnjs.cloudflare.com/ajax/libs/highlight.js/11.9.0/es/languages/go.min.js';
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342 | hljs.registerLanguage('go', go);
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343 | </script>
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344 |
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345 | ````
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346 |
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347 |
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348 | #### jsdelivr ([link](https://www.jsdelivr.com/package/gh/highlightjs/cdn-release))
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349 |
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350 | ##### Common JS <!-- omit in toc -->
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351 |
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352 | ```html
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353 | <link rel="stylesheet" href="https://cdn.jsdelivr.net/gh/highlightjs/cdn-release@11.9.0/build/styles/default.min.css">
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354 | <script src="https://cdn.jsdelivr.net/gh/highlightjs/cdn-release@11.9.0/build/highlight.min.js"></script>
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355 | <!-- and it's easy to individually load additional languages -->
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356 | <script src="https://cdn.jsdelivr.net/gh/highlightjs/cdn-release@11.9.0/build/languages/go.min.js"></script>
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357 | ```
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358 |
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359 | ##### ES6 Modules <!-- omit in toc -->
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360 |
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361 | ```html
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362 | <link rel="stylesheet" href="https://cdn.jsdelivr.net/gh/highlightjs/cdn-release@11.9.0/build/styles/default.min.css">
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363 | <script type="module">
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364 | import hljs from 'https://cdn.jsdelivr.net/gh/highlightjs/cdn-release@11.9.0/build/es/highlight.min.js';
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365 | // and it's easy to individually load additional languages
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366 | import go from 'https://cdn.jsdelivr.net/gh/highlightjs/cdn-release@11.9.0/build/es/languages/go.min.js';
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367 | hljs.registerLanguage('go', go);
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368 | </script>
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369 | ```
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370 |
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371 | #### unpkg ([link](https://unpkg.com/browse/@highlightjs/cdn-assets/))
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372 |
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373 | ##### Common JS <!-- omit in toc -->
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374 |
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375 | ```html
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376 | <link rel="stylesheet" href="https://unpkg.com/@highlightjs/cdn-assets@11.9.0/styles/default.min.css">
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377 | <script src="https://unpkg.com/@highlightjs/cdn-assets@11.9.0/highlight.min.js"></script>
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378 | <!-- and it's easy to individually load additional languages -->
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379 | <script src="https://unpkg.com/@highlightjs/cdn-assets@11.9.0/languages/go.min.js"></script>
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380 | ```
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381 |
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382 | ##### ES6 Modules <!-- omit in toc -->
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383 |
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384 | ```html
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385 | <link rel="stylesheet" href="https://unpkg.com/@highlightjs/cdn-assets@11.9.0/styles/default.min.css">
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386 | <script type="module">
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387 | import hljs from 'https://unpkg.com/@highlightjs/cdn-assets@11.9.0/es/highlight.min.js';
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388 | // and it's easy to individually load & register additional languages
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389 | import go from 'https://unpkg.com/@highlightjs/cdn-assets@11.9.0/es/languages/go.min.js';
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390 | hljs.registerLanguage('go', go);
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391 | </script>
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392 | ```
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393 |
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394 |
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395 | **Note:** *The CDN-hosted `highlight.min.js` package doesn't bundle every language.* It would be
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396 | very large. You can find our list of "common" languages that we bundle by default on our [download page][5].
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397 |
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398 | #### Download prebuilt CDN assets
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399 |
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400 | 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](https://github.com/highlightjs/cdn-release) GitHub repository. You can easily pull individual files off the CDN endpoints with `curl`, etc; if say you only needed `highlight.min.js` and a single CSS file.
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401 |
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402 | There is also an npm package [@highlightjs/cdn-assets](https://www.npmjs.com/package/@highlightjs/cdn-assets) if pulling the assets in via `npm` or `yarn` would be easier for your build process.
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403 |
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404 | ### Download from our website
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405 |
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406 | The [download page][5] can quickly generate a custom single-file minified bundle including only the languages you desire.
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407 |
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408 | **Note:** [Building from source](#build-from-source) can produce slightly smaller builds than the website download.
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409 |
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410 |
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411 | ### Install via NPM package
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412 |
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413 | Our NPM package including all supported languages can be installed with NPM or Yarn:
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414 |
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415 | ```bash
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416 | npm install highlight.js
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417 | # or
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418 | yarn add highlight.js
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419 | ```
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420 |
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421 | Alternatively, you can build the NPM package from source.
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422 |
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423 |
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424 | ### Build from Source
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425 |
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426 | The [current source code][10] is always available on GitHub.
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427 |
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428 | ```bash
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429 | node tools/build.js -t node
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430 | node tools/build.js -t browser :common
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431 | node tools/build.js -t cdn :common
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432 | ```
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433 |
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434 | See our [building documentation][6] for more information.
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435 |
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436 |
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437 | ## Requirements
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438 |
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439 | 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:
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440 |
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441 | - Node.js >= 12.x
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442 | - npm >= 6.x
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443 |
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444 | ## License
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445 |
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446 | Highlight.js is released under the BSD License. See our [LICENSE][7] file
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447 | for details.
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448 |
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449 |
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450 | ## Links
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451 |
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452 | The official website for the library is <https://highlightjs.org/>.
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453 |
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454 | Further in-depth documentation for the API and other topics is at
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455 | <http://highlightjs.readthedocs.io/>.
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456 |
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457 | A list of the Core Team and contributors can be found in the [CONTRIBUTORS.md][8] file.
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458 |
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459 | [1]: http://highlightjs.readthedocs.io/en/latest/api.html#highlightall
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460 | [2]: http://highlightjs.readthedocs.io/en/latest/css-classes-reference.html
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461 | [3]: http://highlightjs.readthedocs.io/en/latest/api.html#highlightelement
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462 | [4]: http://highlightjs.readthedocs.io/en/latest/api.html#configure
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463 | [5]: https://highlightjs.org/download/
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464 | [6]: http://highlightjs.readthedocs.io/en/latest/building-testing.html
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465 | [7]: https://github.com/highlightjs/highlight.js/blob/main/LICENSE
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466 | [8]: https://github.com/highlightjs/highlight.js/blob/main/CONTRIBUTORS.md
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467 | [9]: https://github.com/highlightjs/highlight.js/blob/main/SUPPORTED_LANGUAGES.md
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468 | [10]: https://github.com/highlightjs/
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