IE 11 smooth scrolling not firing intermediate scr

Question

If we make a simple test case like:

document.documentElement.addEventListener('scroll', function() {
    console.log(document.documentElement.scrollTop);
});

And then go and scroll using the scrollbar by clicking the track, or by using PageDown/PageUp, then we can see that we only get one event at the end of the scrolling animation.

Now theoretically I could fix some of that behaviour by simulating the scroll events. Example code with jQuery and Underscore:

$(function () {
    var $document = $(document), until = 0;

    var throttleScroll = _.throttle(function () {
        $document.scroll();
        if (+new Date < until) {
            setTimeout(throttleScroll, 50);
        }
    }, 50);

    $document.keydown(function (evt) {
        if (evt.which === 33 || evt.which === 34) {
            until = +new Date + 300;
            throttleScroll();
        }
    });
});

But it still does not work. We only get scroll events with the original scrollTop and the destination scrollTop, no values in between.

If then go and console.log(document.documentElement.scrollTop) every 10ms, then we can see that IE just does not update the scrollTop as it scrolls.

This is very frustrating if we want to "pin" something to the scroll position. It gets jerky with IE.

I did not observe this behaviour on any other browser, and did not test with previous IE versions.

If anyone has found a way to fix IE's behaviour (maybe there's a magic CSS to turn off smooth scrolling in IE 11?) then I would very much like to hear about it!

Thanks :-)

Answer 1

The issue you're describing is limited to instances of Internet Explorer 11 running on Windows 7. This problem doesn't affect the platform upon which IE 11 was born, Windows 8.1. It seems as though IE 11 on Windows 7 falls into a similar category as other scrolling implementations mentioned above. It's not ideal, but it's something we have to work with/around for the time being.

I'm going to continue looking into this; in fact, just dug a Windows 7 machine out of the closet to setup first thing in the morning so as to investigate further. While we cannot address this head-on, perhaps, maybe, there's a way we can circumvent the problem itself.

To be continued.

Answer 2

Looks like there's a post on IE and forcing a screen "paint" to help with drag-drop. Seems the opposite of most performance efforts but might work? https://stackoverflow.com/a/12395506/906526 (code from https://stackoverflow.com/users/315083/george)

function cleanDisplay() {
    var c = document.createElement('div');
    c.innerHTML = 'x';
    c.style.visibility = 'hidden';
    c.style.height = '1px';
    document.body.insertBefore(c, document.body.firstChild);
    window.setTimeout(function() {document.body.removeChild(c)}, 1);
}

You might try CSS animations so the browser handles animation/ transition. Eg applying a show/ hide class on scroll and, CSS animation.

.hide-remove {
    -webkit-animation: bounceIn 2.5s;
    animation: bounceIn 2.5s;
}

.hide-add {
    -webkit-animation: flipOutX 2.5s;
    animation: flipOutX 2.5s;
    display: block !important;
}

If not having a browser handle animation (with creative css), keyframes and JS performance might offer leads. As a plus, I've seen several sites with navigation bars that "reappear" after scroll end.

Answer 3

You said: "If anyone has found a way to fix IE's behaviour (maybe there's a magic CSS to turn off smooth scrolling in IE 11?) then I would very much like to hear about it!"

This does not turn it off, but here is what I use to resolve the smooth scroll issue in ie with Fixed elements.

if(navigator.userAgent.match(/Trident\/7\./)) {
    $('body').on("mousewheel", function ( event ) {
        event.preventDefault();
        var wd = event.wheelDelta;
        var csp = window.pageYOffset;
        window.scrollTo(0, csp - wd);
    });
}

Answer 4

As a crazy last resort (seems not so crazy actually if the issue is critical) - maybe turn off native scrolling completely and use custom scrolling (i.e. http://jscrollpane.kelvinluck.com/)? And bind onscroll stuff to its custom events: http://jscrollpane.kelvinluck.com/events.html