Detect If A Scroll Event Is Triggered Manually In Jquery

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

Solution 1:

Maybe :animated selector will help you:

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

Demo

Solution 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.

Solution 3:

Using @Tony's accepted answer and @DanielTonon's comment I came up with the following solution:

var animatedScroll = false;
  var lastAnimatedScroll = false;
  $(window).scroll(function(event){
    lastAnimatedScroll = animatedScroll;
    animatedScroll = $('html, body').is(':animated');
  });

This seems to solve the issue mentioned whereby jquery removes the .is(':animated') then scrolls one more pixel, which leads to .is(':animated') ending on a false. By storing the second to last version of .is(':animated') you can be (more) sure whether or not the scroll was an animated one or not.

When you want to know if the scroll was animated or not just check the lastAnimatedScroll variable.

This has NOT been thoroughly tested by me but has been correct on many page refreshes so I will assume it works well enough.

Solution 4:

After attempting to implement the various solutions in this issue I came up with a different approach that is working well for me.

I use a manual boolean for whether an animation is running:

var isRunningAnimation = false;

and set it to true just before animating, and false in the jQuery animate callback function:

  isRunningAnimation = true;

  $('html').animate({
    scrollLeft: 100,
    scrollTop:  100
  }, 400, 'swing', function() {
    isRunningAnimation = false;
  });

and then in the scroll listener just check that boolean:

$('scroll', function() {
  if (!isRunningAnimation) {
    // If we made it to here, the animation isn't running
  }
});

Of course technically if the user decides to manually scroll during the animation, that won't trigger the on scroll logic either, but that seems like enough of an edge case to not worry about.

Solution 5:

I would suggest First of all create a javascript function

// Attaching scroll event when document/window is loadedfunctionOnFirstLoad() {
        if (document.attachEvent) {
            document.attachEvent('onscroll', scrollEvent);
        } elseif (document.addEventListener) {
            document.addEventListener('scroll', scrollEvent, false);
        }

    }

then, use either

window.onload = OnFirstLoad;

Or

    $(document).ready(function () {
         OnFirstLoad();
    });

In This scroll event is a function

functionscrollEvent(e) {
        var body = document.body,
             html = document.documentElement;

        var docHeight = Math.max(body.scrollHeight, body.offsetHeight,
                               html.clientHeight, html.scrollHeight, html.offsetHeight);
        var currentScroll = (document.documentElement && document.documentElement.scrollTop) || document.body.scrollTop;
        // implement your logic according to requirement

    }