Adapted PerfectScrollbar for BODY tag.

/*! Copyright (c) 2011 Brandon Aaron (http://brandonaaron.net)
 * Licensed under the MIT License (LICENSE.txt).
 *
 * Thanks to: http://adomas.org/javascript-mouse-wheel/ for some pointers.
 * Thanks to: Mathias Bank(http://www.mathias-bank.de) for a scope bug fix.
 * Thanks to: Seamus Leahy for adding deltaX and deltaY
 *
 * Version: 3.0.6
 *
 * Requires: 1.2.2+
 */

(function($) {

var types = ['DOMMouseScroll', 'mousewheel'];

if ($.event.fixHooks) {
    for ( var i=types.length; i; ) {
        $.event.fixHooks[ types[--i] ] = $.event.mouseHooks;
    }
}

$.event.special.mousewheel = {
    setup: function() {
        if ( this.addEventListener ) {
            for ( var i=types.length; i; ) {
                this.addEventListener( types[--i], handler, false );
            }
        } else {
            this.onmousewheel = handler;
        }
    },

    teardown: function() {
        if ( this.removeEventListener ) {
            for ( var i=types.length; i; ) {
                this.removeEventListener( types[--i], handler, false );
            }
        } else {
            this.onmousewheel = null;
        }
    }
};

$.fn.extend({
    mousewheel: function(fn) {
        return fn ? this.bind("mousewheel", fn) : this.trigger("mousewheel");
    },

    unmousewheel: function(fn) {
        return this.unbind("mousewheel", fn);
    }
});


function handler(event) {
    var orgEvent = event || window.event, args = [].slice.call( arguments, 1 ), delta = 0, returnValue = true, deltaX = 0, deltaY = 0;
    event = $.event.fix(orgEvent);
    event.type = "mousewheel";

    // Old school scrollwheel delta
    if ( orgEvent.wheelDelta ) { delta = orgEvent.wheelDelta/120; }
    if ( orgEvent.detail     ) { delta = -orgEvent.detail/3; }

    // New school multidimensional scroll (touchpads) deltas
    deltaY = delta;

    // Gecko
    if ( orgEvent.axis !== undefined && orgEvent.axis === orgEvent.HORIZONTAL_AXIS ) {
        deltaY = 0;
        deltaX = -1*delta;
    }

    // Webkit
    if ( orgEvent.wheelDeltaY !== undefined ) { deltaY = orgEvent.wheelDeltaY/120; }
    if ( orgEvent.wheelDeltaX !== undefined ) { deltaX = -1*orgEvent.wheelDeltaX/120; }

    // Add event and delta to the front of the arguments
    args.unshift(event, delta, deltaX, deltaY);

    return ($.event.dispatch || $.event.handle).apply(this, args);
}

})(jQuery);

/************************************************************************************************************************************************/

/* Copyright (c) 2012 HyeonJe Jun (http://github.com/noraesae)
 * Licensed under the MIT License
 * Updated by Nolesh Feb 2014. Now it can be used for BODY and HTML tags.
 * How to use:
 * $('html').css({"overflow":"hidden"});
 * $('html, body').perfectScrollbar({wheelSpeed:50});
 * $('body').perfectScrollbar('update'); //to update
 */
'use strict';
(function (factory) {
  if (typeof define === 'function' && define.amd) {
    // AMD. Register as an anonymous module.
    define(['jquery'], factory);
  } else {
    // Browser globals
    factory(jQuery);
  }
}(function ($) {

  // The default settings for the plugin
  var defaultSettings = {
    wheelSpeed: 10,
    wheelPropagation: false,
    minScrollbarLength: null,
    useBothWheelAxes: false,
    useKeyboard: true,
    suppressScrollX: false,
    suppressScrollY: false,
    scrollXMarginOffset: 0,
    scrollYMarginOffset: 0
  };

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

    return this.each(function () {
      // Use the default settings
      var settings = $.extend(true, {}, defaultSettings),
          $this = $(this);

      if (typeof suppliedSettings === "object") {
        // But over-ride any supplied
        $.extend(true, settings, suppliedSettings);
      } else {
        // If no settings were 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

      // Set class to the container
      $this.addClass('ps-container');

      var $scrollbarXRail = $("<div class='ps-scrollbar-x-rail'></div>").appendTo($this),
          $scrollbarYRail = $("<div class='ps-scrollbar-y-rail'></div>").appendTo($this),
          $scrollbarX = $("<div class='ps-scrollbar-x'></div>").appendTo($scrollbarXRail),
          $scrollbarY = $("<div class='ps-scrollbar-y'></div>").appendTo($scrollbarYRail),
          scrollbarXActive,
          scrollbarYActive,
          containerWidth,
          containerHeight,
          contentWidth,
          contentHeight,
          scrollbarXWidth,
          scrollbarXLeft,
          scrollbarXBottom = parseInt($scrollbarXRail.css('bottom'), 10),
          scrollbarYHeight,
          scrollbarYTop,
          scrollbarYRight = parseInt($scrollbarYRail.css('right'), 10),
          isSmoothScrolling;

      var getSettingsAdjustedThumbSize = function (thumbSize) {
        if (settings.minScrollbarLength) {
          thumbSize = Math.max(thumbSize, settings.minScrollbarLength);
        }
        return thumbSize;
      };

      var updateScrollbarCss = function () {
        $scrollbarXRail.css({position: isSmoothScrolling ? 'fixed' : 'absolute', left: isSmoothScrolling ? 0 : $this.scrollLeft(), bottom: scrollbarXBottom - $this.scrollTop(),
        width: containerWidth, display: settings.suppressScrollX ? "none": "inherit"});
        $scrollbarYRail.css({position: isSmoothScrolling ? 'fixed' : 'absolute', top: isSmoothScrolling ? 0 : $this.scrollTop(), right: scrollbarYRight - $this.scrollLeft(),
        height: containerHeight, display: settings.suppressScrollY ? "none": "inherit"});
        $scrollbarX.css({left: scrollbarXLeft, width: scrollbarXWidth});
        $scrollbarY.css({top: scrollbarYTop, height: scrollbarYHeight});
      };

      var updateBarSizeAndPosition = function () {

        containerWidth = window.innerWidth;
        containerHeight = window.innerHeight;
        contentWidth = $(document).innerWidth();
        contentHeight = $(document).innerHeight();

        if (!settings.suppressScrollX && containerWidth + settings.scrollXMarginOffset < contentWidth) {
          scrollbarXActive = true;
          scrollbarXWidth = getSettingsAdjustedThumbSize(parseInt(containerWidth * containerWidth / contentWidth, 10));
          scrollbarXLeft = parseInt($this.scrollLeft() * (containerWidth - scrollbarXWidth) / (contentWidth - containerWidth), 10);
        }
        else {
          scrollbarXActive = false;
          scrollbarXWidth = 0;
          scrollbarXLeft = 0;
          $this.scrollLeft(0);
        }

        if (!settings.suppressScrollY && containerHeight + settings.scrollYMarginOffset < contentHeight) {
          scrollbarYActive = true;
          scrollbarYHeight = getSettingsAdjustedThumbSize(parseInt(containerHeight * containerHeight / contentHeight, 10));
          scrollbarYTop = parseInt($this.scrollTop() * (containerHeight - scrollbarYHeight) / (contentHeight - containerHeight), 10);
        }
        else {
          scrollbarYActive = false;
          scrollbarYHeight = 0;
          scrollbarYTop = 0;
          $this.scrollTop(0);
        }

        if (scrollbarYTop >= containerHeight - scrollbarYHeight) {
          scrollbarYTop = containerHeight - scrollbarYHeight;
        }
        if (scrollbarXLeft >= containerWidth - scrollbarXWidth) {
          scrollbarXLeft = containerWidth - scrollbarXWidth;
        }

        updateScrollbarCss();
      };

      var bindMouseScrollXHandler = function () {
        var currentLeft,
            currentPageX;

        $scrollbarX.bind('mousedown.perfect-scrollbar', function (e) {
          currentPageX = e.pageX-$scrollbarXRail.offset().left;
          currentLeft = $scrollbarX.position().left;
          $scrollbarXRail.addClass('in-scrolling');
          e.stopPropagation();
          e.preventDefault();
        });

        $(document).bind('mousemove.perfect-scrollbar', function (e) {
          if ($scrollbarXRail.hasClass('in-scrolling')) {

            var halfOfScrollbarLength = parseInt(scrollbarXWidth / 2, 10),
            positionLeft = e.pageX - $scrollbarXRail.offset().left - currentPageX+currentLeft,

            maxPositionLeft = containerWidth - scrollbarXWidth,
            positionRatio = positionLeft / maxPositionLeft;

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


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

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

        $(document).bind('mouseup.perfect-scrollbar', function (e) {
          if ($scrollbarXRail.hasClass('in-scrolling')) {
            $scrollbarXRail.removeClass('in-scrolling');
          }
        });

        currentLeft =
        currentPageX = null;
      };

      var bindMouseScrollYHandler = function () {
        var currentTop,
            currentPageY;

        $scrollbarY.bind('mousedown.perfect-scrollbar', function (e) {
          currentPageY = e.pageY-$scrollbarYRail.offset().top;
          currentTop = $scrollbarY.position().top;
          $scrollbarYRail.addClass('in-scrolling');
          e.stopPropagation();
          e.preventDefault();
        });

        $(document).bind('mousemove.perfect-scrollbar', function (e) {
          if ($scrollbarYRail.hasClass('in-scrolling')) {

            var halfOfScrollbarLength = parseInt(scrollbarYHeight / 2, 10),
            positionTop = e.pageY - $scrollbarYRail.offset().top - currentPageY+currentTop,

            maxPositionTop = containerHeight - scrollbarYHeight,
            positionRatio = positionTop / maxPositionTop;

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


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

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

        $(document).bind('mouseup.perfect-scrollbar', function (e) {
          if ($scrollbarYRail.hasClass('in-scrolling')) {
            $scrollbarYRail.removeClass('in-scrolling');
          }
        });

        currentTop =
        currentPageY = null;
      };

      // bind handlers
      var bindMouseWheelHandler = function () {
        var shouldPreventDefault = function (deltaX, deltaY) {
          var scrollTop = $this.scrollTop();
          if (scrollTop === 0 && deltaY > 0 && deltaX === 0) {
            return !settings.wheelPropagation;
          }
          else if (scrollTop >= contentHeight - containerHeight && deltaY < 0 && deltaX === 0) {
            return !settings.wheelPropagation;
          }

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

        var shouldPrevent = false;
        $this.bind('mousewheel.perfect-scrollbar', function (e, delta, deltaX, deltaY) {
          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));
            }
          } 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));
            }
          }

          // update bar position
          updateBarSizeAndPosition();

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

        // fix Firefox scroll problem
        $this.bind('MozMousePixelScroll.perfect-scrollbar', function (e) {
          if (shouldPrevent) {
            e.preventDefault();
          }
        });
      };

      var bindKeyboardHandler = function () {
        var shouldPreventDefault = function (deltaX, deltaY) {
          var scrollTop = $this.scrollTop();
          if (scrollTop === 0 && deltaY > 0 && deltaX === 0) {
             return false;
          }
          else if (scrollTop >= contentHeight - containerHeight && deltaY < 0 && deltaX === 0) {
             return false;
          }

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

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

        var shouldPrevent = false;
        $(document).bind('keydown.perfect-scrollbar', function (e) {
          if (!hovered) {
            return;
          }

          var deltaX = 0,
              deltaY = 0;

          switch (e.which) {
          case 37: // left
            deltaX = -3;
            break;
          case 38: // up
            deltaY = 3;
            break;
          case 39: // right
            deltaX = 3;
            break;
          case 40: // down
            deltaY = -3;
            break;
          default:
            return;
          }
          $this.scrollTop($this.scrollTop() - (deltaY * settings.wheelSpeed));
          $this.scrollLeft($this.scrollLeft() + (deltaX * settings.wheelSpeed));

          // update bar position
          updateBarSizeAndPosition();

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

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

        $scrollbarY.bind('click.perfect-scrollbar', stopPropagation);
        $scrollbarYRail.bind('click.perfect-scrollbar', function (e) {                                  console.log('bindRailClickHandler');
          var halfOfScrollbarLength = parseInt(scrollbarYHeight / 2, 10),
              positionTop = e.pageY - $scrollbarYRail.offset().top - halfOfScrollbarLength,
              maxPositionTop = containerHeight - scrollbarYHeight,
              positionRatio = positionTop / maxPositionTop;

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

            isSmoothScrolling=true;
            $this.stop().animate({scrollTop: (contentHeight - containerHeight) * positionRatio}, {
                duration: 1000,
                step: function() {
                    updateBarSizeAndPosition();
                },
                complete: function(){
                    isSmoothScrolling=false;
                    updateBarSizeAndPosition();
                }
            });
        });

        $scrollbarX.bind('click.perfect-scrollbar', stopPropagation);
        $scrollbarXRail.bind('click.perfect-scrollbar', function (e) {
          var halfOfScrollbarLength = parseInt(scrollbarXWidth / 2, 10),
              positionLeft = e.pageX - $scrollbarXRail.offset().left - halfOfScrollbarLength,
              maxPositionLeft = containerWidth - scrollbarXWidth,
              positionRatio = positionLeft / maxPositionLeft;

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

          isSmoothScrolling=true;
          $this.stop().animate({scrollLeft: (contentWidth - containerWidth) * positionRatio}, {
                duration: 1000,
                step: function() {
                    updateBarSizeAndPosition();
                },
                complete: function(){
                    isSmoothScrolling=false;
                    updateBarSizeAndPosition();
                }
          });

        });
      };

      // bind mobile touch handler
      var bindMobileTouchHandler = function () {
        var applyTouchMove = function (differenceX, differenceY) {
          $this.scrollTop($this.scrollTop() - differenceY);
          $this.scrollLeft($this.scrollLeft() - differenceX);

          // update bar position
          updateBarSizeAndPosition();
        };

        var startCoords = {},
            startTime = 0,
            speed = {},
            breakingProcess = null,
            inGlobalTouch = false;

        $(window).bind("touchstart.perfect-scrollbar", function (e) {
          inGlobalTouch = true;
        });
        $(window).bind("touchend.perfect-scrollbar", function (e) {
          inGlobalTouch = false;
        });

        $this.bind("touchstart.perfect-scrollbar", function (e) {
          var touch = e.originalEvent.targetTouches[0];

          startCoords.pageX = touch.pageX;
          startCoords.pageY = touch.pageY;

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

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

          e.stopPropagation();
        });
        $this.bind("touchmove.perfect-scrollbar", function (e) {
          if (!inGlobalTouch && e.originalEvent.targetTouches.length === 1) {
            var touch = e.originalEvent.targetTouches[0];

            var currentCoords = {};
            currentCoords.pageX = touch.pageX;
            currentCoords.pageY = touch.pageY;

            var differenceX = currentCoords.pageX - startCoords.pageX,
              differenceY = currentCoords.pageY - startCoords.pageY;

            applyTouchMove(differenceX, differenceY);
            startCoords = currentCoords;

            var currentTime = (new Date()).getTime();
            speed.x = differenceX / (currentTime - startTime);
            speed.y = differenceY / (currentTime - startTime);
            startTime = currentTime;

            e.preventDefault();
          }
        });
        $this.bind("touchend.perfect-scrollbar", function (e) {
          clearInterval(breakingProcess);
          breakingProcess = setInterval(function () {
            if (Math.abs(speed.x) < 0.01 && Math.abs(speed.y) < 0.01) {
              clearInterval(breakingProcess);
              return;
            }

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

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

      var destroy = function () {
        $this.unbind('.perfect-scrollbar');
        $(window).unbind('.perfect-scrollbar');
        $(document).unbind('.perfect-scrollbar');
        $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
        $scrollbarX =
        $scrollbarY =
        containerWidth =
        containerHeight =
        contentWidth =
        contentHeight =
        scrollbarXWidth =
        scrollbarXLeft =
        scrollbarXBottom =
        scrollbarYHeight =
        scrollbarYTop =
        scrollbarYRight = null;
      };

      var ieSupport = function (version) {
        $this.addClass('ie').addClass('ie' + version);

        var bindHoverHandlers = function () {
          var mouseenter = function () {
            $(this).addClass('hover');
          };
          var mouseleave = function () {
            $(this).removeClass('hover');
          };
          $this.bind('mouseenter.perfect-scrollbar', mouseenter).bind('mouseleave.perfect-scrollbar', mouseleave);
          $scrollbarXRail.bind('mouseenter.perfect-scrollbar', mouseenter).bind('mouseleave.perfect-scrollbar', mouseleave);
          $scrollbarYRail.bind('mouseenter.perfect-scrollbar', mouseenter).bind('mouseleave.perfect-scrollbar', mouseleave);
          $scrollbarX.bind('mouseenter.perfect-scrollbar', mouseenter).bind('mouseleave.perfect-scrollbar', mouseleave);
          $scrollbarY.bind('mouseenter.perfect-scrollbar', mouseenter).bind('mouseleave.perfect-scrollbar', mouseleave);
        };

        var fixIe6ScrollbarPosition = function () {
          updateScrollbarCss = function () {
            $scrollbarX.css({left: scrollbarXLeft + $this.scrollLeft(), bottom: scrollbarXBottom, width: scrollbarXWidth});
            $scrollbarY.css({top: scrollbarYTop + $this.scrollTop(), right: scrollbarYRight, height: scrollbarYHeight});
            $scrollbarX.hide().show();
            $scrollbarY.hide().show();
          };
          updateContentScrollTop = function () {
            var scrollTop = parseInt(scrollbarYTop * contentHeight / containerHeight, 10);
            $this.scrollTop(scrollTop);
            $scrollbarX.css({bottom: scrollbarXBottom});
            $scrollbarX.hide().show();
          };
          updateContentScrollLeft = function () {
            var scrollLeft = parseInt(scrollbarXLeft * contentWidth / containerWidth, 10);
            $this.scrollLeft(scrollLeft);
            $scrollbarY.hide().show();
          };
        };

        if (version === 6) {
          bindHoverHandlers();
          fixIe6ScrollbarPosition();
        }
      };

      var supportsTouch = (('ontouchstart' in window) || window.DocumentTouch && document instanceof window.DocumentTouch);

      var initialize = function () {
        var ieMatch = navigator.userAgent.toLowerCase().match(/(msie) ([\w.]+)/);
        if (ieMatch && ieMatch[1] === 'msie') {
          // must be executed at first, because 'ieSupport' may addClass to the container
          ieSupport(parseInt(ieMatch[2], 10));
        }

        $.browser.chrome = /chrom(e|ium)/.test(navigator.userAgent.toLowerCase());
        if($.browser.chrome){
            $this = $('body');
        }
        else $this = $('body, html');

        updateBarSizeAndPosition();
        bindMouseScrollXHandler();
        bindMouseScrollYHandler();
        bindRailClickHandler();
        if (supportsTouch) {
          bindMobileTouchHandler();
        }
        if ($this.mousewheel) {
          bindMouseWheelHandler();
        }
        if (settings.useKeyboard) {
          bindKeyboardHandler();
        }
        $this.data('perfect-scrollbar', $this);
        $this.data('perfect-scrollbar-update', updateBarSizeAndPosition);
        $this.data('perfect-scrollbar-destroy', destroy);
      };

      // initialize
      initialize();

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