Traditionally SEOs have been suspicious of JavaScript, but it’s an inescapable part of the modern web, Google & Bing began rendering content with the current version of Chromium in 2019, thus supporting ES6, rendering content on the client using JavaScript has been less risky for indexation

As such, just like HTML, SEOs need to have at least a rudimentary understanding of JavaScript to help with forensic technical SEO.

A lot has changed in front end development in the 15 years since I first learned JavaScript, so it seemed like a good idea for a refresher. Moreover my impression is that vanilla JavaScript is increasingly in fashion with Front End developers, mainly due to performance.

I took a few courses, and would recommend these in particular:

Beginner JavaScript. It’s $139 for what took me around 100 hours of videos and tinkering with the examples. The creator has a breezy style (at one point taking a call from his mother mid-lesson) that makes it a fun course.

Modern JavaScript is a course available only on O’Reilly, but if you do have access, I would recommend the concise, well thought out explanations, that go in to more detail and more advanced topics.

After a lot of review-reading; JavaScript: The Definitive Guide seems to be the best soup to nuts JavaScript book. Make sure you get the 7th edition, previous editions are cheaper, but predate ES6, so a lot of the syntax is out of date.

A nice concept in Beginner JavaScript is ‘cardio’ – grinding out hours of examples and small projects to fully understand a topic, I built my own to-do list (RIP Wunderlist), an browser version of a word game my wife and I play (source) and various little calculators.

I’d recommend learning JavaScript for any technical SEO, and as C based language, it will feel familiar for anyone who is already uses Python, or give you a head start if you learn in future.