Detect if a scroll event is triggered manually in jQuery

Question

This question was already asked here a long time ago:

Detect jquery event trigger by user or call by code

But it has never been answered conclusively (or maybe I'm simply not able to search properly).

Is it possible to detect whether a scroll event has been triggered by the user or by the jQuery animate function?

I am trying to prevent the scroll event to trigger itself while doing something like this:

$(document).scroll(function(){
    $("html").stop(true);
    var number = 400; //some other stuff is happening here
    clearTimeout(tout);
    tout = setTimeout(function(){
        if(top == $(document).scrollTop()){
            $("html").animate({
                scrollTop: (number),
                easing: "easeInQuad",
                duration: 110
            });
        }
    },120);
});

This code seems to be suitable:

$('#scroller').scroll(function(e) {
    if (e.originalEvent) {
        console.log('scroll happen manual scroll');
    } else {
        console.log('scroll happen by call');
    }
});

But the originalEvent object isn't able to detect the animate trigger properly.

Is there any other way to do this?

Answer 1

Maybe :animated selector will help you:

$('#scroller').scroll(function(e) {
    if ($(this).is(':animated')) {
        console.log('scroll happen by animate');
    } else if (e.originalEvent) {
        // scroll happen manual scroll
        console.log('scroll happen manual scroll');
    } else {
        // scroll happen by call
        console.log('scroll happen by call');
    }
});

Demo

Answer 2

I don't know how well this works with touch screen devices but this works for me on desktop at least

$(window).on('mousewheel', function(){
    //code that will only fire on manual scroll input
});

$(window).scroll(function(){
    //code that will fire on both mouse scroll and code based scroll
});

I don't think there is a way to only target the animated scroll (the accepted answer didn't work for me).

UPDATE: Warning!

Unfortunately, 'mousewheel' doesn't seem to pick up on users who manually grab the scroll bar and drag it or users who use the scroll bar arrow buttons :(

This still works ok for touch screen devices as their swipes seem to count as mouse scrolls. This isn't a great solution for desktop users though.