How to Detect if a User is Scrolling with JavaScript?

To detect if a user is scrolling with JavaScript, we can watch for scroll events by adding event handlers.

For instance, we can write:

let userHasScrolled = false;  
window.onscroll = (e) => {  
  userHasScrolled = true;  
}

to add the userHasScrolled variable.

Then we set the window.onscroll property to a function that runs when we scroll.

Also, we can use the addEventListener method to add the scroll event listener.

For instance, we can write:

let userHasScrolled = false;  
window.addEventListener('scroll', (e) => {  
  userHasScrolled = true;  
})

We call window.addEventListener with 'scroll' to listen to the scroll event.

The 2nd argument is the event handler that’s run when the scroll event is emitted when we scroll.