perfect-scrollbar/src/perfect-scrollbar.js

/* Copyright (c) 2012, 2014 Hyunje Alex Jun and other contributors
 * Licensed under the MIT License
 */
(function (factory) {
  'use strict';

  if (typeof define === 'function' && define.amd) {
    // AMD. Register as an anonymous module.
    define(['jquery'], factory);
  } else if (typeof exports === 'object') {
    // Node/CommonJS
    factory(require('jquery'));
  } else {
    // Browser globals
    factory(jQuery);
  }
})(function ($) {
  'use strict';

  function getInt(x) {
    if (typeof x === 'string') {
      return parseInt(x, 10);
    } else {
      return ~~x;
    }
  }

  var defaultSettings = {
    wheelSpeed: 1,
    wheelPropagation: false,
    swipePropagation: true,
    minScrollbarLength: null,
    maxScrollbarLength: null,
    useBothWheelAxes: false,
    useKeyboard: true,
    suppressScrollX: false,
    suppressScrollY: false,
    scrollXMarginOffset: 0,
    scrollYMarginOffset: 0,
    includePadding: false
  };

  var incrementingId = 0;
  var eventClassFactory = function () {
    var id = incrementingId++;
    return function (eventName) {
      var className = '.perfect-scrollbar-' + id;
      if (typeof eventName === 'undefined') {
        return className;
      } else {
        return eventName + className;
      }
    };
  };

  var isWebkit = 'WebkitAppearance' in document.documentElement.style;

  $.fn.perfectScrollbar = function (suppliedSettings, option) {

    return this.each(function () {
      var settings = $.extend(true, {}, defaultSettings);
      var $this = $(this);
      var isPluginAlive = function () { return !!$this; };

      if (typeof suppliedSettings === "object") {
        // Override default settings with any supplied
        $.extend(true, settings, suppliedSettings);
      } else {
        // If no setting was supplied, then the first param must be the option
        option = suppliedSettings;
      }

      // Catch options
      if (option === 'update') {
        if ($this.data('perfect-scrollbar-update')) {
          $this.data('perfect-scrollbar-update')();
        }
        return $this;
      }
      else if (option === 'destroy') {
        if ($this.data('perfect-scrollbar-destroy')) {
          $this.data('perfect-scrollbar-destroy')();
        }
        return $this;
      }

      if ($this.data('perfect-scrollbar')) {
        // if there's already perfect-scrollbar
        return $this.data('perfect-scrollbar');
      }


      // Or generate new perfectScrollbar

      $this.addClass('ps-container');

      var containerWidth;
      var containerHeight;
      var contentWidth;
      var contentHeight;

      var isRtl = $this.css('direction') === "rtl";
      var eventClass = eventClassFactory();
      var ownerDocument = this.ownerDocument || document;

      var $scrollbarXRail = $("<div class='ps-scrollbar-x-rail'>").appendTo($this);
      var $scrollbarX = $("<div class='ps-scrollbar-x'>").appendTo($scrollbarXRail);
      var scrollbarXActive;
      var scrollbarXWidth;
      var scrollbarXLeft;
      var scrollbarXBottom = getInt($scrollbarXRail.css('bottom'));
      var isScrollbarXUsingBottom = scrollbarXBottom === scrollbarXBottom; // !isNaN
      var scrollbarXTop = isScrollbarXUsingBottom ? null : getInt($scrollbarXRail.css('top'));
      var railBorderXWidth = getInt($scrollbarXRail.css('borderLeftWidth')) + getInt($scrollbarXRail.css('borderRightWidth'));
      var railXMarginWidth = getInt($scrollbarXRail.css('marginLeft')) + getInt($scrollbarXRail.css('marginRight'));
      var railXWidth;

      var $scrollbarYRail = $("<div class='ps-scrollbar-y-rail'>").appendTo($this);
      var $scrollbarY = $("<div class='ps-scrollbar-y'>").appendTo($scrollbarYRail);
      var scrollbarYActive;
      var scrollbarYHeight;
      var scrollbarYTop;
      var scrollbarYRight = getInt($scrollbarYRail.css('right'));
      var isScrollbarYUsingRight = scrollbarYRight === scrollbarYRight; // !isNaN
      var scrollbarYLeft = isScrollbarYUsingRight ? null : getInt($scrollbarYRail.css('left'));
      var railBorderYWidth = getInt($scrollbarYRail.css('borderTopWidth')) + getInt($scrollbarYRail.css('borderBottomWidth'));
      var railYMarginHeight = getInt($scrollbarYRail.css('marginTop')) + getInt($scrollbarYRail.css('marginBottom'));
      var railYHeight;

      function updateScrollTop(currentTop, deltaY) {
        var newTop = currentTop + deltaY;
        var maxTop = containerHeight - scrollbarYHeight;

        if (newTop < 0) {
          scrollbarYTop = 0;
        } else if (newTop > maxTop) {
          scrollbarYTop = maxTop;
        } else {
          scrollbarYTop = newTop;
        }

        var scrollTop = getInt(scrollbarYTop * (contentHeight - containerHeight) / (containerHeight - scrollbarYHeight));
        $this.scrollTop(scrollTop);
      }

      function updateScrollLeft(currentLeft, deltaX) {
        var newLeft = currentLeft + deltaX;
        var maxLeft = containerWidth - scrollbarXWidth;

        if (newLeft < 0) {
          scrollbarXLeft = 0;
        } else if (newLeft > maxLeft) {
          scrollbarXLeft = maxLeft;
        } else {
          scrollbarXLeft = newLeft;
        }

        var scrollLeft = getInt(scrollbarXLeft * (contentWidth - containerWidth) / (containerWidth - scrollbarXWidth));
        $this.scrollLeft(scrollLeft);
      }

      function getThumbSize(thumbSize) {
        if (settings.minScrollbarLength) {
          thumbSize = Math.max(thumbSize, settings.minScrollbarLength);
        }
        if (settings.maxScrollbarLength) {
          thumbSize = Math.min(thumbSize, settings.maxScrollbarLength);
        }
        return thumbSize;
      }

      function updateCss() {
        var xRailOffset = {width: railXWidth};
        if (isRtl) {
          xRailOffset.left = $this.scrollLeft() + containerWidth - contentWidth;
        } else {
          xRailOffset.left = $this.scrollLeft();
        }
        if (isScrollbarXUsingBottom) {
          xRailOffset.bottom = scrollbarXBottom - $this.scrollTop();
        } else {
          xRailOffset.top = scrollbarXTop + $this.scrollTop();
        }
        $scrollbarXRail.css(xRailOffset);

        var railYOffset = {top: $this.scrollTop(), height: railYHeight};

        if (isScrollbarYUsingRight) {
          if (isRtl) {
            railYOffset.right = contentWidth - $this.scrollLeft() - scrollbarYRight - $scrollbarY.outerWidth();
          } else {
            railYOffset.right = scrollbarYRight - $this.scrollLeft();
          }
        } else {
          if (isRtl) {
            railYOffset.left = $this.scrollLeft() + containerWidth * 2 - contentWidth - scrollbarYLeft - $scrollbarY.outerWidth();
          } else {
            railYOffset.left = scrollbarYLeft + $this.scrollLeft();
          }
        }
        $scrollbarYRail.css(railYOffset);

        $scrollbarX.css({left: scrollbarXLeft, width: scrollbarXWidth - railBorderXWidth});
        $scrollbarY.css({top: scrollbarYTop, height: scrollbarYHeight - railBorderYWidth});
      }

      function updateGeometry() {
        // Hide scrollbars not to affect scrollWidth and scrollHeight
        $this.removeClass('ps-active-x');
        $this.removeClass('ps-active-y');

        containerWidth = settings.includePadding ? $this.innerWidth() : $this.width();
        containerHeight = settings.includePadding ? $this.innerHeight() : $this.height();
        contentWidth = $this.prop('scrollWidth');
        contentHeight = $this.prop('scrollHeight');

        if (!settings.suppressScrollX && containerWidth + settings.scrollXMarginOffset < contentWidth) {
          scrollbarXActive = true;
          railXWidth = containerWidth - railXMarginWidth;
          scrollbarXWidth = getThumbSize(getInt(railXWidth * containerWidth / contentWidth));
          scrollbarXLeft = getInt($this.scrollLeft() * (railXWidth - scrollbarXWidth) / (contentWidth - containerWidth));
        } else {
          scrollbarXActive = false;
          scrollbarXWidth = 0;
          scrollbarXLeft = 0;
          $this.scrollLeft(0);
        }

        if (!settings.suppressScrollY && containerHeight + settings.scrollYMarginOffset < contentHeight) {
          scrollbarYActive = true;
          railYHeight = containerHeight - railYMarginHeight;
          scrollbarYHeight = getThumbSize(getInt(railYHeight * containerHeight / contentHeight));
          scrollbarYTop = getInt($this.scrollTop() * (railYHeight - scrollbarYHeight) / (contentHeight - containerHeight));
        } else {
          scrollbarYActive = false;
          scrollbarYHeight = 0;
          scrollbarYTop = 0;
          $this.scrollTop(0);
        }

        if (scrollbarXLeft >= railXWidth - scrollbarXWidth) {
          scrollbarXLeft = railXWidth - scrollbarXWidth;
        }
        if (scrollbarYTop >= railYHeight - scrollbarYHeight) {
          scrollbarYTop = railYHeight - scrollbarYHeight;
        }

        updateCss();

        if (scrollbarXActive) {
          $this.addClass('ps-active-x');
        }
        if (scrollbarYActive) {
          $this.addClass('ps-active-y');
        }
      }

      function bindMouseScrollXHandler() {
        var currentLeft;
        var currentPageX;

        var mouseMoveHandler = function (e) {
          updateScrollLeft(currentLeft, e.pageX - currentPageX);
          updateGeometry();
          e.stopPropagation();
          e.preventDefault();
        };

        var mouseUpHandler = function (e) {
          $scrollbarXRail.removeClass('in-scrolling');
          $(ownerDocument).unbind(eventClass('mousemove'), mouseMoveHandler);
        };

        $scrollbarX.bind(eventClass('mousedown'), function (e) {
          currentPageX = e.pageX;
          currentLeft = $scrollbarX.position().left;
          $scrollbarXRail.addClass('in-scrolling');

          $(ownerDocument).bind(eventClass('mousemove'), mouseMoveHandler);
          $(ownerDocument).one(eventClass('mouseup'), mouseUpHandler);

          e.stopPropagation();
          e.preventDefault();
        });

        currentLeft =
        currentPageX = null;
      }

      function bindMouseScrollYHandler() {
        var currentTop;
        var currentPageY;

        var mouseMoveHandler = function (e) {
          updateScrollTop(currentTop, e.pageY - currentPageY);
          updateGeometry();
          e.stopPropagation();
          e.preventDefault();
        };

        var mouseUpHandler = function (e) {
          $scrollbarYRail.removeClass('in-scrolling');
          $(ownerDocument).unbind(eventClass('mousemove'), mouseMoveHandler);
        };

        $scrollbarY.bind(eventClass('mousedown'), function (e) {
          currentPageY = e.pageY;
          currentTop = $scrollbarY.position().top;
          $scrollbarYRail.addClass('in-scrolling');

          $(ownerDocument).bind(eventClass('mousemove'), mouseMoveHandler);
          $(ownerDocument).one(eventClass('mouseup'), mouseUpHandler);

          e.stopPropagation();
          e.preventDefault();
        });

        currentTop =
        currentPageY = null;
      }

      function shouldPreventWheel(deltaX, deltaY) {
        var scrollTop = $this.scrollTop();
        if (deltaX === 0) {
          if (!scrollbarYActive) {
            return false;
          }
          if ((scrollTop === 0 && deltaY > 0) || (scrollTop >= contentHeight - containerHeight && deltaY < 0)) {
            return !settings.wheelPropagation;
          }
        }

        var scrollLeft = $this.scrollLeft();
        if (deltaY === 0) {
          if (!scrollbarXActive) {
            return false;
          }
          if ((scrollLeft === 0 && deltaX < 0) || (scrollLeft >= contentWidth - containerWidth && deltaX > 0)) {
            return !settings.wheelPropagation;
          }
        }
        return true;
      }

      function shouldPreventSwipe(deltaX, deltaY) {
        var scrollTop = $this.scrollTop();
        var scrollLeft = $this.scrollLeft();
        var magnitudeX = Math.abs(deltaX);
        var magnitudeY = Math.abs(deltaY);

        if (magnitudeY > magnitudeX) {
          // user is perhaps trying to swipe up/down the page

          if (((deltaY < 0) && (scrollTop === contentHeight - containerHeight)) ||
              ((deltaY > 0) && (scrollTop === 0))) {
            return !settings.swipePropagation;
          }
        } else if (magnitudeX > magnitudeY) {
          // user is perhaps trying to swipe left/right across the page

          if (((deltaX < 0) && (scrollLeft === contentWidth - containerWidth)) ||
              ((deltaX > 0) && (scrollLeft === 0))) {
            return !settings.swipePropagation;
          }
        }

        return true;
      }

      function bindMouseWheelHandler() {
        var shouldPrevent = false;

        function getDeltaFromEvent(e) {
          var deltaX = e.originalEvent.deltaX;
          var deltaY = -1 * e.originalEvent.deltaY;

          if (typeof deltaX === "undefined" || typeof deltaY === "undefined") {
            // OS X Safari
            deltaX = -1 * e.originalEvent.wheelDeltaX / 6;
            deltaY = e.originalEvent.wheelDeltaY / 6;
          }

          if (e.originalEvent.deltaMode && e.originalEvent.deltaMode === 1) {
            // Firefox in deltaMode 1: Line scrolling
            deltaX *= 10;
            deltaY *= 10;
          }

          if (deltaX !== deltaX && deltaY !== deltaY/* NaN checks */) {
            // IE in some mouse drivers
            deltaX = 0;
            deltaY = e.originalEvent.wheelDelta;
          }

          return [deltaX, deltaY];
        }

        function mousewheelHandler(e) {
          // FIXME: this is a quick fix for the select problem in FF and IE.
          // If there comes an effective way to deal with the problem,
          // this lines should be removed.
          if (!isWebkit && $this.find('select:focus').length > 0) {
            return;
          }

          var delta = getDeltaFromEvent(e);

          var deltaX = delta[0];
          var deltaY = delta[1];

          shouldPrevent = false;
          if (!settings.useBothWheelAxes) {
            // deltaX will only be used for horizontal scrolling and deltaY will
            // only be used for vertical scrolling - this is the default
            $this.scrollTop($this.scrollTop() - (deltaY * settings.wheelSpeed));
            $this.scrollLeft($this.scrollLeft() + (deltaX * settings.wheelSpeed));
          } else if (scrollbarYActive && !scrollbarXActive) {
            // only vertical scrollbar is active and useBothWheelAxes option is
            // active, so let's scroll vertical bar using both mouse wheel axes
            if (deltaY) {
              $this.scrollTop($this.scrollTop() - (deltaY * settings.wheelSpeed));
            } else {
              $this.scrollTop($this.scrollTop() + (deltaX * settings.wheelSpeed));
            }
            shouldPrevent = true;
          } else if (scrollbarXActive && !scrollbarYActive) {
            // useBothWheelAxes and only horizontal bar is active, so use both
            // wheel axes for horizontal bar
            if (deltaX) {
              $this.scrollLeft($this.scrollLeft() + (deltaX * settings.wheelSpeed));
            } else {
              $this.scrollLeft($this.scrollLeft() - (deltaY * settings.wheelSpeed));
            }
            shouldPrevent = true;
          }

          updateGeometry();

          shouldPrevent = (shouldPrevent || shouldPreventWheel(deltaX, deltaY));
          if (shouldPrevent) {
            e.stopPropagation();
            e.preventDefault();
          }
        }

        if (typeof window.onwheel !== "undefined") {
          $this.bind(eventClass('wheel'), mousewheelHandler);
        } else if (typeof window.onmousewheel !== "undefined") {
          $this.bind(eventClass('mousewheel'), mousewheelHandler);
        }
      }

      function bindKeyboardHandler() {
        var hovered = false;
        $this.bind(eventClass('mouseenter'), function (e) {
          hovered = true;
        });
        $this.bind(eventClass('mouseleave'), function (e) {
          hovered = false;
        });

        var shouldPrevent = false;
        $(ownerDocument).bind(eventClass('keydown'), function (e) {
          if (e.isDefaultPrevented && e.isDefaultPrevented()) {
            return;
          }

          if (!hovered) {
            return;
          }

          var activeElement = document.activeElement ? document.activeElement : ownerDocument.activeElement;
          // go deeper if element is a webcomponent
          while (activeElement.shadowRoot) {
            activeElement = activeElement.shadowRoot.activeElement;
          }
          if ($(activeElement).is(":input,[contenteditable]")) {
            return;
          }

          var deltaX = 0;
          var deltaY = 0;

          switch (e.which) {
          case 37: // left
            deltaX = -30;
            break;
          case 38: // up
            deltaY = 30;
            break;
          case 39: // right
            deltaX = 30;
            break;
          case 40: // down
            deltaY = -30;
            break;
          case 33: // page up
            deltaY = 90;
            break;
          case 32: // space bar
          case 34: // page down
            deltaY = -90;
            break;
          case 35: // end
            if (e.ctrlKey) {
              deltaY = -contentHeight;
            } else {
              deltaY = -containerHeight;
            }
            break;
          case 36: // home
            if (e.ctrlKey) {
              deltaY = $this.scrollTop();
            } else {
              deltaY = containerHeight;
            }
            break;
          default:
            return;
          }

          $this.scrollTop($this.scrollTop() - deltaY);
          $this.scrollLeft($this.scrollLeft() + deltaX);

          shouldPrevent = shouldPreventWheel(deltaX, deltaY);
          if (shouldPrevent) {
            e.preventDefault();
          }
        });
      }

      function bindRailClickHandler() {
        function stopPropagation(e) { e.stopPropagation(); }

        $scrollbarY.bind(eventClass('click'), stopPropagation);
        $scrollbarYRail.bind(eventClass('click'), function (e) {
          var halfOfScrollbarLength = getInt(scrollbarYHeight / 2);
          var positionTop = e.pageY - $scrollbarYRail.offset().top - halfOfScrollbarLength;
          var maxPositionTop = containerHeight - scrollbarYHeight;
          var positionRatio = positionTop / maxPositionTop;

          if (positionRatio < 0) {
            positionRatio = 0;
          } else if (positionRatio > 1) {
            positionRatio = 1;
          }

          $this.scrollTop((contentHeight - containerHeight) * positionRatio);
        });

        $scrollbarX.bind(eventClass('click'), stopPropagation);
        $scrollbarXRail.bind(eventClass('click'), function (e) {
          var halfOfScrollbarLength = getInt(scrollbarXWidth / 2);
          var positionLeft = e.pageX - $scrollbarXRail.offset().left - halfOfScrollbarLength;
          var maxPositionLeft = containerWidth - scrollbarXWidth;
          var positionRatio = positionLeft / maxPositionLeft;

          if (positionRatio < 0) {
            positionRatio = 0;
          } else if (positionRatio > 1) {
            positionRatio = 1;
          }

          $this.scrollLeft((contentWidth - containerWidth) * positionRatio);
        });
      }

      function bindSelectionHandler() {
        function getRangeNode() {
          var selection = window.getSelection ? window.getSelection() :
                          document.getSlection ? document.getSlection() : {rangeCount: 0};
          if (selection.rangeCount === 0) {
            return null;
          } else {
            return selection.getRangeAt(0).commonAncestorContainer;
          }
        }

        var scrollingLoop = null;
        var scrollDiff = {top: 0, left: 0};
        function startScrolling() {
          if (!scrollingLoop) {
            scrollingLoop = setInterval(function () {
              if (!isPluginAlive()) {
                clearInterval(scrollingLoop);
                return;
              }

              $this.scrollTop($this.scrollTop() + scrollDiff.top);
              $this.scrollLeft($this.scrollLeft() + scrollDiff.left);
              updateGeometry();
            }, 50); // every .1 sec
          }
        }
        function stopScrolling() {
          if (scrollingLoop) {
            clearInterval(scrollingLoop);
            scrollingLoop = null;
          }
          $scrollbarXRail.removeClass('in-scrolling');
          $scrollbarYRail.removeClass('in-scrolling');
        }

        var isSelected = false;
        $(ownerDocument).bind(eventClass('selectionchange'), function (e) {
          if ($.contains($this[0], getRangeNode())) {
            isSelected = true;
          } else {
            isSelected = false;
            stopScrolling();
          }
        });
        $(window).bind(eventClass('mouseup'), function (e) {
          if (isSelected) {
            isSelected = false;
            stopScrolling();
          }
        });

        $(window).bind(eventClass('mousemove'), function (e) {
          if (isSelected) {
            var mousePosition = {x: e.pageX, y: e.pageY};
            var containerOffset = $this.offset();
            var containerGeometry = {
              left: containerOffset.left,
              right: containerOffset.left + $this.outerWidth(),
              top: containerOffset.top,
              bottom: containerOffset.top + $this.outerHeight()
            };

            if (mousePosition.x < containerGeometry.left + 3) {
              scrollDiff.left = -5;
              $scrollbarXRail.addClass('in-scrolling');
            } else if (mousePosition.x > containerGeometry.right - 3) {
              scrollDiff.left = 5;
              $scrollbarXRail.addClass('in-scrolling');
            } else {
              scrollDiff.left = 0;
            }

            if (mousePosition.y < containerGeometry.top + 3) {
              if (containerGeometry.top + 3 - mousePosition.y < 5) {
                scrollDiff.top = -5;
              } else {
                scrollDiff.top = -20;
              }
              $scrollbarYRail.addClass('in-scrolling');
            } else if (mousePosition.y > containerGeometry.bottom - 3) {
              if (mousePosition.y - containerGeometry.bottom + 3 < 5) {
                scrollDiff.top = 5;
              } else {
                scrollDiff.top = 20;
              }
              $scrollbarYRail.addClass('in-scrolling');
            } else {
              scrollDiff.top = 0;
            }

            if (scrollDiff.top === 0 && scrollDiff.left === 0) {
              stopScrolling();
            } else {
              startScrolling();
            }
          }
        });
      }

      function bindTouchHandler(supportsTouch, supportsIePointer) {
        function applyTouchMove(differenceX, differenceY) {
          $this.scrollTop($this.scrollTop() - differenceY);
          $this.scrollLeft($this.scrollLeft() - differenceX);

          updateGeometry();
        }

        var startOffset = {};
        var startTime = 0;
        var speed = {};
        var easingLoop = null;
        var inGlobalTouch = false;
        var inLocalTouch = false;

        function globalTouchStart(e) {
          inGlobalTouch = true;
        }
        function globalTouchEnd(e) {
          inGlobalTouch = false;
        }

        function getTouch(e) {
          if (e.originalEvent.targetTouches) {
            return e.originalEvent.targetTouches[0];
          } else {
            // Maybe IE pointer
            return e.originalEvent;
          }
        }
        function shouldHandle(e) {
          var event = e.originalEvent;
          if (event.targetTouches && event.targetTouches.length === 1) {
            return true;
          }
          if (event.pointerType && event.pointerType !== 'mouse' && event.pointerType !== event.MSPOINTER_TYPE_MOUSE) {
            return true;
          }
          return false;
        }
        function touchStart(e) {
          if (shouldHandle(e)) {
            inLocalTouch = true;

            var touch = getTouch(e);

            startOffset.pageX = touch.pageX;
            startOffset.pageY = touch.pageY;

            startTime = (new Date()).getTime();

            if (easingLoop !== null) {
              clearInterval(easingLoop);
            }

            e.stopPropagation();
          }
        }
        function touchMove(e) {
          if (!inGlobalTouch && inLocalTouch && shouldHandle(e)) {
            var touch = getTouch(e);

            var currentOffset = {pageX: touch.pageX, pageY: touch.pageY};

            var differenceX = currentOffset.pageX - startOffset.pageX;
            var differenceY = currentOffset.pageY - startOffset.pageY;

            applyTouchMove(differenceX, differenceY);
            startOffset = currentOffset;

            var currentTime = (new Date()).getTime();

            var timeGap = currentTime - startTime;
            if (timeGap > 0) {
              speed.x = differenceX / timeGap;
              speed.y = differenceY / timeGap;
              startTime = currentTime;
            }

            if (shouldPreventSwipe(differenceX, differenceY)) {
              e.stopPropagation();
              e.preventDefault();
            }
          }
        }
        function touchEnd(e) {
          if (!inGlobalTouch && inLocalTouch) {
            inLocalTouch = false;

            clearInterval(easingLoop);
            easingLoop = setInterval(function () {
              if (!isPluginAlive()) {
                clearInterval(easingLoop);
                return;
              }

              if (Math.abs(speed.x) < 0.01 && Math.abs(speed.y) < 0.01) {
                clearInterval(easingLoop);
                return;
              }

              applyTouchMove(speed.x * 30, speed.y * 30);

              speed.x *= 0.8;
              speed.y *= 0.8;
            }, 10);
          }
        }

        if (supportsTouch) {
          $(window).bind(eventClass("touchstart"), globalTouchStart);
          $(window).bind(eventClass("touchend"), globalTouchEnd);
          $this.bind(eventClass("touchstart"), touchStart);
          $this.bind(eventClass("touchmove"), touchMove);
          $this.bind(eventClass("touchend"), touchEnd);
        }

        if (supportsIePointer) {
          if (window.PointerEvent) {
            $(window).bind(eventClass("pointerdown"), globalTouchStart);
            $(window).bind(eventClass("pointerup"), globalTouchEnd);
            $this.bind(eventClass("pointerdown"), touchStart);
            $this.bind(eventClass("pointermove"), touchMove);
            $this.bind(eventClass("pointerup"), touchEnd);
          } else if (window.MSPointerEvent) {
            $(window).bind(eventClass("MSPointerDown"), globalTouchStart);
            $(window).bind(eventClass("MSPointerUp"), globalTouchEnd);
            $this.bind(eventClass("MSPointerDown"), touchStart);
            $this.bind(eventClass("MSPointerMove"), touchMove);
            $this.bind(eventClass("MSPointerUp"), touchEnd);
          }
        }
      }

      function bindScrollHandler() {
        $this.bind(eventClass('scroll'), function (e) {
          updateGeometry();
        });
      }

      function destroy() {
        $this.unbind(eventClass());
        $(window).unbind(eventClass());
        $(ownerDocument).unbind(eventClass());
        $this.data('perfect-scrollbar', null);
        $this.data('perfect-scrollbar-update', null);
        $this.data('perfect-scrollbar-destroy', null);
        $scrollbarX.remove();
        $scrollbarY.remove();
        $scrollbarXRail.remove();
        $scrollbarYRail.remove();

        // clean all variables
        $this =
        $scrollbarXRail =
        $scrollbarYRail =
        $scrollbarX =
        $scrollbarY =
        scrollbarXActive =
        scrollbarYActive =
        containerWidth =
        containerHeight =
        contentWidth =
        contentHeight =
        scrollbarXWidth =
        scrollbarXLeft =
        scrollbarXBottom =
        isScrollbarXUsingBottom =
        scrollbarXTop =
        scrollbarYHeight =
        scrollbarYTop =
        scrollbarYRight =
        isScrollbarYUsingRight =
        scrollbarYLeft =
        isRtl =
        eventClass = null;
      }

      var supportsTouch = (('ontouchstart' in window) || window.DocumentTouch && document instanceof window.DocumentTouch);
      var supportsIePointer = window.navigator.msMaxTouchPoints !== null;

      function initialize() {
        updateGeometry();
        bindScrollHandler();
        bindMouseScrollXHandler();
        bindMouseScrollYHandler();
        bindRailClickHandler();
        bindSelectionHandler();
        bindMouseWheelHandler();

        if (supportsTouch || supportsIePointer) {
          bindTouchHandler(supportsTouch, supportsIePointer);
        }
        if (settings.useKeyboard) {
          bindKeyboardHandler();
        }
        $this.data('perfect-scrollbar', $this);
        $this.data('perfect-scrollbar-update', updateGeometry);
        $this.data('perfect-scrollbar-destroy', destroy);
      }

      initialize();

      return $this;
    });
  };
});