Using requestIdleCallback

In this lab, you will learn about the requestIdleCallback function, which can be used to schedule work to run when the browser is idle. This can be particularly useful when performing non-essential tasks that shouldn't interfere with the browser's main work, such as rendering and user input handling.

You will start by creating a simple HTML page with a button and a div element. You will then implement a JavaScript function that uses the requestIdleCallback to change the text inside the div only when the browser has idle time, simulating a task that shouldn't block the main thread.

By the end of this lab, you should have a solid understanding of the requestIdleCallback function and how to use it effectively to improve your web applications' performance.