javascript - Scroll the page on drag with jQuery

Question

I have tried using kinetic.js and the code below, however when I try this in IE11 it keeps jumping to the top every time I scroll:

$("html").kinetic();

I want to make the page scrollable on tablets and IE10 and 11 so that users can just push the page up to scroll down as you would on mobile devices.

How can I do this in pure-JS or jQuery without it jumping to the top?

Answer 1

You can do this quite simply by recording the position of the mouse when clicked, and the current position when being dragged. Try this:

var clicked = false, clickY;
$(document).on({
    'mousemove': function(e) {
        clicked && updateScrollPos(e);
    },
    'mousedown': function(e) {
        clicked = true;
        clickY = e.pageY;
    },
    'mouseup': function() {
        clicked = false;
        $('html').css('cursor', 'auto');
    }
});

var updateScrollPos = function(e) {
    $('html').css('cursor', 'row-resize');
    $(window).scrollTop($(window).scrollTop() + (clickY - e.pageY));
}

To prevent text selection while dragging, add the following CSS:

body {
    -webkit-touch-callout: none;
    -webkit-user-select: none;
    -khtml-user-select: none;
    -moz-user-select: none;
    -ms-user-select: none;
    user-select: none;
}

Example fiddle

---

Update

Here's an version of the above as a jQuery plugin, extended to allow both vertical and horizontal scrolling via the settings. It also allows you to change the cursor that's used too.

(function($) {
  $.dragScroll = function(options) {
    var settings = $.extend({
      scrollVertical: true,
      scrollHorizontal: true,
      cursor: null
    }, options);

    var clicked = false,
      clickY, clickX;

    var getCursor = function() {
      if (settings.cursor) return settings.cursor;
      if (settings.scrollVertical && settings.scrollHorizontal) return 'move';
      if (settings.scrollVertical) return 'row-resize';
      if (settings.scrollHorizontal) return 'col-resize';
    }

    var updateScrollPos = function(e, el) {
      $('html').css('cursor', getCursor());
      var $el = $(el);
      settings.scrollVertical && $el.scrollTop($el.scrollTop() + (clickY - e.pageY));
      settings.scrollHorizontal && $el.scrollLeft($el.scrollLeft() + (clickX - e.pageX));
    }

    $(document).on({
      'mousemove': function(e) {
        clicked && updateScrollPos(e, this);
      },
      'mousedown': function(e) {
        clicked = true;
        clickY = e.pageY;
        clickX = e.pageX;
      },
      'mouseup': function() {
        clicked = false;
        $('html').css('cursor', 'auto');
      }
    });
  }
}(jQuery))

$.dragScroll();

/* Note: CSS is not relevant to the solution. 
   This is only needed for this demonstration */

body,
html {
  padding: 0;
  margin: 0;
}

div {
  height: 1000px;
  width: 2000px;
  border-bottom: 3px dashed #EEE;
  /* gradient is only to make the scroll movement more obvious */
  background: rgba(201, 2, 2, 1);
  background: -moz-linear-gradient(-125deg, rgba(201, 2, 2, 1) 0%, rgba(204, 0, 204, 1) 16%, rgba(94, 0, 201, 1) 31%, rgba(0, 153, 199, 1) 43%, rgba(0, 199, 119, 1) 56%, rgba(136, 199, 0, 1) 69%, rgba(199, 133, 0, 1) 83%, rgba(107, 0, 0, 1) 100%);
  background: -webkit-gradient(left top, right bottom, color-stop(0%, rgba(201, 2, 2, 1)), color-stop(16%, rgba(204, 0, 204, 1)), color-stop(31%, rgba(94, 0, 201, 1)), color-stop(43%, rgba(0, 153, 199, 1)), color-stop(56%, rgba(0, 199, 119, 1)), color-stop(69%, rgba(136, 199, 0, 1)), color-stop(83%, rgba(199, 133, 0, 1)), color-stop(100%, rgba(107, 0, 0, 1)));
  background: -webkit-linear-gradient(-125deg, rgba(201, 2, 2, 1) 0%, rgba(204, 0, 204, 1) 16%, rgba(94, 0, 201, 1) 31%, rgba(0, 153, 199, 1) 43%, rgba(0, 199, 119, 1) 56%, rgba(136, 199, 0, 1) 69%, rgba(199, 133, 0, 1) 83%, rgba(107, 0, 0, 1) 100%);
  background: -o-linear-gradient(-125deg, rgba(201, 2, 2, 1) 0%, rgba(204, 0, 204, 1) 16%, rgba(94, 0, 201, 1) 31%, rgba(0, 153, 199, 1) 43%, rgba(0, 199, 119, 1) 56%, rgba(136, 199, 0, 1) 69%, rgba(199, 133, 0, 1) 83%, rgba(107, 0, 0, 1) 100%);
  background: -ms-linear-gradient(-125deg, rgba(201, 2, 2, 1) 0%, rgba(204, 0, 204, 1) 16%, rgba(94, 0, 201, 1) 31%, rgba(0, 153, 199, 1) 43%, rgba(0, 199, 119, 1) 56%, rgba(136, 199, 0, 1) 69%, rgba(199, 133, 0, 1) 83%, rgba(107, 0, 0, 1) 100%);
  background: linear-gradient(-110deg, rgba(201, 2, 2, 1) 0%, rgba(204, 0, 204, 1) 16%, rgba(94, 0, 201, 1) 31%, rgba(0, 153, 199, 1) 43%, rgba(0, 199, 119, 1) 56%, rgba(136, 199, 0, 1) 69%, rgba(199, 133, 0, 1) 83%, rgba(107, 0, 0, 1) 100%);
  filter: progid: DXImageTransform.Microsoft.gradient( startColorstr='#c90202', endColorstr='#6b0000', GradientType=1);
  color: #EEE;
  padding: 20px;
  font-size: 2em;
}

body {
  -webkit-touch-callout: none;
  -webkit-user-select: none;
  -khtml-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div>First...</div>

<div>Second...</div>