[jquery] Can I change the scroll speed using css or jQuery?

In the example below, I would like to reduce the scroll speed of the div's content, especially when using the mouse wheel, as one wheel tick scrolls approximately the div's height.

Is it possible to control that with CSS, and if not, javascript (perhaps using jQuery) ?

.scrollable {_x000D_
    width: 500px;_x000D_
    height: 70px;_x000D_
    overflow: auto; _x000D_
}

<div class="scrollable">_x000D_
    Sed ut perspiciatis unde omnis iste natus error sit voluptatem accusantium doloremque laudantium, totam rem aperiam, eaque ipsa quae ab illo inventore veritatis et quasi architecto beatae vitae dicta sunt explicabo. Nemo enim ipsam voluptatem quia voluptas sit aspernatur aut odit aut fugit, sed quia consequuntur magni dolores eos qui ratione voluptatem sequi nesciunt. Neque porro quisquam est, qui dolorem ipsum quia dolor sit amet, consectetur, adipisci velit, sed quia non numquam eius modi tempora incidunt ut labore et dolore magnam aliquam quaerat voluptatem. Ut enim ad minima veniam, quis nostrum exercitationem ullam corporis suscipit laboriosam, nisi ut aliquid ex ea commodi consequatur? Quis autem vel eum iure reprehenderit qui in ea voluptate velit esse quam nihil molestiae consequatur, vel illum qui dolorem eum fugiat quo voluptas nulla pariatur?_x000D_
</div>

Note: I realize that the scroll speed might differ between os/browers and browser settings. But I think that in the majority of the cases, the scroll speed (when using the mouse wheel) is too fast, so I would like to slow it down.

I just made a pure Javascript function based on that code. Javascript only version demo: http://jsbin.com/copidifiji

That is the independent code from jQuery

if (window.addEventListener) {window.addEventListener('DOMMouseScroll', wheel, false); 
window.onmousewheel = document.onmousewheel = wheel;}

function wheel(event) {
    var delta = 0;
    if (event.wheelDelta) delta = (event.wheelDelta)/120 ;
    else if (event.detail) delta = -(event.detail)/3;

    handle(delta);
    if (event.preventDefault) event.preventDefault();
    event.returnValue = false;
}

function handle(sentido) {
    var inicial = document.body.scrollTop;
    var time = 1000;
    var distance = 200;
  animate({
    delay: 0,
    duration: time,
    delta: function(p) {return p;},
    step: function(delta) {
window.scrollTo(0, inicial-distance*delta*sentido);   
    }});}

function animate(opts) {
  var start = new Date();
  var id = setInterval(function() {
    var timePassed = new Date() - start;
    var progress = (timePassed / opts.duration);
    if (progress > 1) {progress = 1;}
    var delta = opts.delta(progress);
    opts.step(delta);
    if (progress == 1) {clearInterval(id);}}, opts.delay || 10);
}

The scroll speed CAN be changed, adjusted, reversed, all of the above - via javascript (or a js library such as jQuery).

WHY would you want to do this? Parallax is just one of the reasons. I have no idea why anyone would argue against doing so -- the same negative arguments can be made against hiding DIVs, sliding elements up/down, etc. Websites are always a combination of technical functionality and UX design -- a good designer can use almost any technical capability to improve UX. That is what makes him/her good.

Toni Almeida of Portugal created a brilliant demo, reproduced below:

jsFiddle Demo

HTML:

<div id="myDiv">
    Use the mouse wheel (not the scroll bar) to scroll this DIV. You will see that the scroll eventually slows down, and then stops. <span class="boldit">Use the mouse wheel (not the scroll bar) to scroll this DIV. You will see that the scroll eventually slows down, and then stops. </span>
</div>

javascript/jQuery:

  function wheel(event) {
      var delta = 0;
      if (event.wheelDelta) {(delta = event.wheelDelta / 120);}
      else if (event.detail) {(delta = -event.detail / 3);}

      handle(delta);
      if (event.preventDefault) {(event.preventDefault());}
      event.returnValue = false;
  }

  function handle(delta) {
      var time = 1000;
      var distance = 300;

      $('html, body').stop().animate({
          scrollTop: $(window).scrollTop() - (distance * delta)
      }, time );
  }

  if (window.addEventListener) {window.addEventListener('DOMMouseScroll', wheel, false);}
    window.onmousewheel = document.onmousewheel = wheel;

Source:

How to change default scrollspeed,scrollamount,scrollinertia of a webpage

Just use this js file. (I mentioned 2 examples with different js files. hope the second one is what you need) You can simply change the scroll amount, speed etc by changing the parameters.

https://github.com/nathco/jQuery.scrollSpeed

Here's a Demo

You can also try this. Here's a demo

No. Scroll speed is determined by the browser (and usually directly by the settings on the computer/device). CSS and Javascript don't (or shouldn't) have any way to affect system settings.

That being said, there are likely a number of ways you could try to fake a different scroll speed by moving your own content around in such a way as to counteract scrolling. However, I think doing so is a HORRIBLE idea in terms of usability, accessibility, and respect for your users, but I would start by finding events that your target browsers fire that indicate scrolling.

Once you can capture the scroll event (assuming you can), then you would be able to adjust your content dynamically so that the portion you want is visible.

Another approach would be to deal with this in Flash, which does give you at least some level of control over scrolling events.