To add JavaScript in Visual Studio Code, you need to install VSCode first and then Node.JS. Once done, create a .JS file, write codes, and then start writing codes.

In addition to executing code embedded in HTML, it's also possible to add a code editor directly into an HTML page using the py-repl tag so that you can input code and execute it, as shown below.

Using Quarto with Observable JavaScript is a great solution for R and Python users who want to create more interactive and visually engaging reports.

The JavaScript is still working behind the scenes. Essentially, we get a more granular HTML syntax, which can just load segments instead of whole pages, and can submit Ajax requests.