I had the need to add syntax highlighting to a page, but I didn’t have the luxury of changing the markup.

Most syntax highlighting libraries, like Prism.js, force you to use a fixed structure like this:

<pre>
<code class="language-js">
...
</code>
</pre>


Citing this:

Prism does its best to encourage good authoring practices. Therefore, it only works with  elements, since marking up code without a element is semantically invalid.

 
 It’s all nice and idealistic and all but I had my code in a div from an outside source. You force me that markup, but I don’t have that. I finally found https://highlightjs.org/ that lets me apply syntax highlighting to any element I want on the page, by loading the library first and then calling: document.addEventListener('DOMContentLoaded', () => { document.querySelectorAll('.my-code-div').forEach((el) => { hljs.highlightElement(el) }) }) Download my free Programming Ebooks!