TamperMonkey Tutorial | Add Custom JavaScript to YouTube.com
Channel: Kaj Stanski
Date: 2021-09-15

https://www.youtube.com/channel/UC84VcYhepRajJlW8XGXeTSA?sub_confirmation=1

How to change a website with your own code? A beginners lesson about practical Greasemonkey scripts.

In this tutorial, I will show you how to inspect the YouTube source code to alter it with JavaScript code injected using a Tampermonkey app / plugin / add-on. This method works on both Firefox and Chrome. You can learn from it as a follow along tutorial to then implement your own scripts altering the webpages of your choice. Such Tampermonkey scripts are useful for displaying additional data / information or for autocompletion of forms to speed up your workflows.