diff --git a/src/DataSet.js b/src/DataSet.js
index ca93ade1..40c16504 100644
--- a/src/DataSet.js
+++ b/src/DataSet.js
@@ -83,7 +83,7 @@ function DataSet (data, options) {
  *                                  {Object | null} params
  *                                  {String | Number} senderId
  */
-DataSet.prototype.on = function on (event, callback) {
+DataSet.prototype.on = function(event, callback) {
   var subscribers = this.subscribers[event];
   if (!subscribers) {
     subscribers = [];
@@ -103,7 +103,7 @@ DataSet.prototype.subscribe = DataSet.prototype.on;
  * @param {String} event
  * @param {function} callback
  */
-DataSet.prototype.off = function off(event, callback) {
+DataSet.prototype.off = function(event, callback) {
   var subscribers = this.subscribers[event];
   if (subscribers) {
     this.subscribers[event] = subscribers.filter(function (listener) {
diff --git a/src/timeline/component/Component.js b/src/timeline/component/Component.js
index 61ce3290..341070dd 100644
--- a/src/timeline/component/Component.js
+++ b/src/timeline/component/Component.js
@@ -16,7 +16,7 @@ function Component () {
  *                          {String | Number | function} [width]
  *                          {String | Number | function} [height]
  */
-Component.prototype.setOptions = function setOptions(options) {
+Component.prototype.setOptions = function(options) {
   if (options) {
     util.extend(this.options, options);
 
@@ -31,7 +31,7 @@ Component.prototype.setOptions = function setOptions(options) {
  * @param {String} name
  * @return {*} value
  */
-Component.prototype.getOption = function getOption(name) {
+Component.prototype.getOption = function(name) {
   var value;
   if (this.options) {
     value = this.options[name];
@@ -46,7 +46,7 @@ Component.prototype.getOption = function getOption(name) {
  * Repaint the component
  * @return {boolean} Returns true if the component is resized
  */
-Component.prototype.redraw = function redraw() {
+Component.prototype.redraw = function() {
   // should be implemented by the component
   return false;
 };
@@ -57,7 +57,7 @@ Component.prototype.redraw = function redraw() {
  * @return {Boolean} Returns true if the component is resized
  * @protected
  */
-Component.prototype._isResized = function _isResized() {
+Component.prototype._isResized = function() {
   var resized = (this.props._previousWidth !== this.props.width ||
       this.props._previousHeight !== this.props.height);
 
diff --git a/src/timeline/component/CurrentTime.js b/src/timeline/component/CurrentTime.js
index 8707292a..f622b0d4 100644
--- a/src/timeline/component/CurrentTime.js
+++ b/src/timeline/component/CurrentTime.js
@@ -21,7 +21,7 @@ CurrentTime.prototype = new Component();
  * Create the HTML DOM for the current time bar
  * @private
  */
-CurrentTime.prototype._create = function _create () {
+CurrentTime.prototype._create = function() {
   var bar = document.createElement('div');
   bar.className = 'currenttime';
   bar.style.position = 'absolute';
@@ -35,7 +35,7 @@ CurrentTime.prototype._create = function _create () {
  * Repaint the component
  * @return {boolean} Returns true if the component is resized
  */
-CurrentTime.prototype.redraw = function redraw() {
+CurrentTime.prototype.redraw = function() {
   if (this.options.showCurrentTime) {
     var parent = this.timeline.dom.backgroundVertical;
     if (this.bar.parentNode != parent) {
@@ -68,7 +68,7 @@ CurrentTime.prototype.redraw = function redraw() {
 /**
  * Start auto refreshing the current time bar
  */
-CurrentTime.prototype.start = function start() {
+CurrentTime.prototype.start = function() {
   var me = this;
 
   function update () {
@@ -92,7 +92,7 @@ CurrentTime.prototype.start = function start() {
 /**
  * Stop auto refreshing the current time bar
  */
-CurrentTime.prototype.stop = function stop() {
+CurrentTime.prototype.stop = function() {
   if (this.currentTimeTimer !== undefined) {
     clearTimeout(this.currentTimeTimer);
     delete this.currentTimeTimer;
diff --git a/src/timeline/component/CustomTime.js b/src/timeline/component/CustomTime.js
index 3ac61096..31ef8dd3 100644
--- a/src/timeline/component/CustomTime.js
+++ b/src/timeline/component/CustomTime.js
@@ -24,7 +24,7 @@ CustomTime.prototype = new Component();
  * Create the DOM for the custom time
  * @private
  */
-CustomTime.prototype._create = function _create () {
+CustomTime.prototype._create = function() {
   var bar = document.createElement('div');
   bar.className = 'customtime';
   bar.style.position = 'absolute';
diff --git a/src/timeline/component/Group.js b/src/timeline/component/Group.js
index 24a57b91..78da0c39 100644
--- a/src/timeline/component/Group.js
+++ b/src/timeline/component/Group.js
@@ -65,7 +65,7 @@ Group.prototype._create = function() {
  * Set the group data for this group
  * @param {Object} data   Group data, can contain properties content and className
  */
-Group.prototype.setData = function setData(data) {
+Group.prototype.setData = function(data) {
   // update contents
   var content = data && data.content;
   if (content instanceof Element) {
@@ -96,7 +96,7 @@ Group.prototype.setData = function setData(data) {
  * Get the width of the group label
  * @return {number} width
  */
-Group.prototype.getLabelWidth = function getLabelWidth() {
+Group.prototype.getLabelWidth = function() {
   return this.props.label.width;
 };
 
@@ -108,7 +108,7 @@ Group.prototype.getLabelWidth = function getLabelWidth() {
  * @param {boolean} [restack=false]  Force restacking of all items
  * @return {boolean} Returns true if the group is resized
  */
-Group.prototype.redraw = function redraw(range, margin, restack) {
+Group.prototype.redraw = function(range, margin, restack) {
   var resized = false;
 
   this.visibleItems = this._updateVisibleItems(this.orderedItems, this.visibleItems, range);
@@ -179,7 +179,7 @@ Group.prototype.redraw = function redraw(range, margin, restack) {
 /**
  * Show this group: attach to the DOM
  */
-Group.prototype.show = function show() {
+Group.prototype.show = function() {
   if (!this.dom.label.parentNode) {
     this.itemSet.dom.labelSet.appendChild(this.dom.label);
   }
@@ -200,7 +200,7 @@ Group.prototype.show = function show() {
 /**
  * Hide this group: remove from the DOM
  */
-Group.prototype.hide = function hide() {
+Group.prototype.hide = function() {
   var label = this.dom.label;
   if (label.parentNode) {
     label.parentNode.removeChild(label);
@@ -226,7 +226,7 @@ Group.prototype.hide = function hide() {
  * Add an item to the group
  * @param {Item} item
  */
-Group.prototype.add = function add(item) {
+Group.prototype.add = function(item) {
   this.items[item.id] = item;
   item.setParent(this);
 
@@ -240,7 +240,7 @@ Group.prototype.add = function add(item) {
  * Remove an item from the group
  * @param {Item} item
  */
-Group.prototype.remove = function remove(item) {
+Group.prototype.remove = function(item) {
   delete this.items[item.id];
   item.setParent(this.itemSet);
 
@@ -255,14 +255,14 @@ Group.prototype.remove = function remove(item) {
  * Remove an item from the corresponding DataSet
  * @param {Item} item
  */
-Group.prototype.removeFromDataSet = function removeFromDataSet(item) {
+Group.prototype.removeFromDataSet = function(item) {
   this.itemSet.removeItem(item.id);
 };
 
 /**
  * Reorder the items
  */
-Group.prototype.order = function order() {
+Group.prototype.order = function() {
   var array = util.toArray(this.items);
   this.orderedItems.byStart = array;
   this.orderedItems.byEnd = this._constructByEndArray(array);
@@ -277,7 +277,7 @@ Group.prototype.order = function order() {
  * @returns {ItemRange[]}
  * @private
  */
-Group.prototype._constructByEndArray = function _constructByEndArray(array) {
+Group.prototype._constructByEndArray = function(array) {
   var endArray = [];
 
   for (var i = 0; i < array.length; i++) {
@@ -296,7 +296,7 @@ Group.prototype._constructByEndArray = function _constructByEndArray(array) {
  * @return {Item[]} visibleItems                            The new visible items.
  * @private
  */
-Group.prototype._updateVisibleItems = function _updateVisibleItems(orderedItems, visibleItems, range) {
+Group.prototype._updateVisibleItems = function(orderedItems, visibleItems, range) {
   var initialPosByStart,
       newVisibleItems = [],
       i;
@@ -359,7 +359,7 @@ Group.prototype._updateVisibleItems = function _updateVisibleItems(orderedItems,
  * @returns {number}
  * @private
  */
-Group.prototype._binarySearch = function _binarySearch(orderedItems, range, byEnd) {
+Group.prototype._binarySearch = function(orderedItems, range, byEnd) {
   var array = [];
   var byTime = byEnd ? 'end' : 'start';
   if (byEnd == true) {array = orderedItems.byEnd;  }
@@ -420,7 +420,7 @@ Group.prototype._binarySearch = function _binarySearch(orderedItems, range, byEn
  * @returns {boolean}
  * @private
  */
-Group.prototype._checkIfInvisible = function _checkIfInvisible(item, visibleItems, range) {
+Group.prototype._checkIfInvisible = function(item, visibleItems, range) {
   if (item.isVisible(range)) {
     if (!item.displayed) item.show();
     item.repositionX();
@@ -445,7 +445,7 @@ Group.prototype._checkIfInvisible = function _checkIfInvisible(item, visibleItem
  * @param {{start:number, end:number}} range
  * @private
  */
-Group.prototype._checkIfVisible = function _checkIfVisible(item, visibleItems, range) {
+Group.prototype._checkIfVisible = function(item, visibleItems, range) {
   if (item.isVisible(range)) {
     if (!item.displayed) item.show();
     // reposition item horizontally
diff --git a/src/timeline/component/ItemSet.js b/src/timeline/component/ItemSet.js
index d8bb8028..0948a67c 100644
--- a/src/timeline/component/ItemSet.js
+++ b/src/timeline/component/ItemSet.js
@@ -7,7 +7,7 @@ var UNGROUPED = '__ungrouped__'; // reserved group id for ungrouped items
  * @param {{dom: Object}} timeline
  * @param {Object} [options]      See ItemSet.setOptions for the available options.
  * @constructor ItemSet
- * @extends Panel
+ * @extends Component
  */
 function ItemSet(timeline, options) {
   this.timeline = timeline;
@@ -75,7 +75,7 @@ ItemSet.types = {
 /**
  * Create the HTML DOM for the ItemSet
  */
-ItemSet.prototype._create = function _create(){
+ItemSet.prototype._create = function(){
   var frame = document.createElement('div');
   frame.className = 'itemset';
   frame['timeline-itemset'] = this;
@@ -162,7 +162,7 @@ ItemSet.prototype.setOptions = Component.prototype.setOptions;
 /**
  * Mark the ItemSet dirty so it will refresh everything with next redraw
  */
-ItemSet.prototype.markDirty = function markDirty() {
+ItemSet.prototype.markDirty = function() {
   this.groupIds = [];
   this.stackDirty = true;
 };
@@ -170,7 +170,7 @@ ItemSet.prototype.markDirty = function markDirty() {
 /**
  * Hide the component from the DOM
  */
-ItemSet.prototype.hide = function hide() {
+ItemSet.prototype.hide = function() {
   // remove the frame containing the items
   if (this.dom.frame.parentNode) {
     this.dom.frame.parentNode.removeChild(this.dom.frame);
@@ -191,7 +191,7 @@ ItemSet.prototype.hide = function hide() {
  * Show the component in the DOM (when not already visible).
  * @return {Boolean} changed
  */
-ItemSet.prototype.show = function show() {
+ItemSet.prototype.show = function() {
   // show frame containing the items
   if (!this.dom.frame.parentNode) {
     this.timeline.dom.center.appendChild(this.dom.frame);
@@ -215,7 +215,7 @@ ItemSet.prototype.show = function show() {
  *                      selected. If ids is an empty array, all items will be
  *                      unselected.
  */
-ItemSet.prototype.setSelection = function setSelection(ids) {
+ItemSet.prototype.setSelection = function(ids) {
   var i, ii, id, item;
 
   if (ids) {
@@ -247,7 +247,7 @@ ItemSet.prototype.setSelection = function setSelection(ids) {
  * Get the selected items by their id
  * @return {Array} ids  The ids of the selected items
  */
-ItemSet.prototype.getSelection = function getSelection() {
+ItemSet.prototype.getSelection = function() {
   return this.selection.concat([]);
 };
 
@@ -256,7 +256,7 @@ ItemSet.prototype.getSelection = function getSelection() {
  * @param {String | Number} id
  * @private
  */
-ItemSet.prototype._deselect = function _deselect(id) {
+ItemSet.prototype._deselect = function(id) {
   var selection = this.selection;
   for (var i = 0, ii = selection.length; i < ii; i++) {
     if (selection[i] == id) { // non-strict comparison!
@@ -270,7 +270,7 @@ ItemSet.prototype._deselect = function _deselect(id) {
  * Repaint the component
  * @return {boolean} Returns true if the component is resized
  */
-ItemSet.prototype.redraw = function redraw() {
+ItemSet.prototype.redraw = function() {
   var margin = this.options.margin,
       range = this.timeline.range,
       asSize = util.option.asSize,
@@ -352,7 +352,7 @@ ItemSet.prototype.redraw = function redraw() {
  * @return {Group | null} firstGroup
  * @private
  */
-ItemSet.prototype._firstGroup = function _firstGroup() {
+ItemSet.prototype._firstGroup = function() {
   var firstGroupIndex = (this.options.orientation == 'top') ? 0 : (this.groupIds.length - 1);
   var firstGroupId = this.groupIds[firstGroupIndex];
   var firstGroup = this.groups[firstGroupId] || this.groups[UNGROUPED];
@@ -365,7 +365,7 @@ ItemSet.prototype._firstGroup = function _firstGroup() {
  * there are no groups specified.
  * @protected
  */
-ItemSet.prototype._updateUngrouped = function _updateUngrouped() {
+ItemSet.prototype._updateUngrouped = function() {
   var ungrouped = this.groups[UNGROUPED];
 
   if (this.groupsData) {
@@ -398,7 +398,7 @@ ItemSet.prototype._updateUngrouped = function _updateUngrouped() {
  * Get the element for the labelset
  * @return {HTMLElement} labelSet
  */
-ItemSet.prototype.getLabelSet = function getLabelSet() {
+ItemSet.prototype.getLabelSet = function() {
   return this.dom.labelSet;
 };
 
@@ -406,7 +406,7 @@ ItemSet.prototype.getLabelSet = function getLabelSet() {
  * Set items
  * @param {vis.DataSet | null} items
  */
-ItemSet.prototype.setItems = function setItems(items) {
+ItemSet.prototype.setItems = function(items) {
   var me = this,
       ids,
       oldItemsData = this.itemsData;
@@ -453,7 +453,7 @@ ItemSet.prototype.setItems = function setItems(items) {
  * Get the current items
  * @returns {vis.DataSet | null}
  */
-ItemSet.prototype.getItems = function getItems() {
+ItemSet.prototype.getItems = function() {
   return this.itemsData;
 };
 
@@ -461,7 +461,7 @@ ItemSet.prototype.getItems = function getItems() {
  * Set groups
  * @param {vis.DataSet} groups
  */
-ItemSet.prototype.setGroups = function setGroups(groups) {
+ItemSet.prototype.setGroups = function(groups) {
   var me = this,
       ids;
 
@@ -513,7 +513,7 @@ ItemSet.prototype.setGroups = function setGroups(groups) {
  * Get the current groups
  * @returns {vis.DataSet | null} groups
  */
-ItemSet.prototype.getGroups = function getGroups() {
+ItemSet.prototype.getGroups = function() {
   return this.groupsData;
 };
 
@@ -521,7 +521,7 @@ ItemSet.prototype.getGroups = function getGroups() {
  * Remove an item by its id
  * @param {String | Number} id
  */
-ItemSet.prototype.removeItem = function removeItem (id) {
+ItemSet.prototype.removeItem = function(id) {
   var item = this.itemsData.get(id),
       dataset = this._myDataSet();
 
@@ -542,7 +542,7 @@ ItemSet.prototype.removeItem = function removeItem (id) {
  * @param {Number[]} ids
  * @protected
  */
-ItemSet.prototype._onUpdate = function _onUpdate(ids) {
+ItemSet.prototype._onUpdate = function(ids) {
   var me = this,
       items = this.items,
       itemOptions = this.itemOptions;
@@ -599,7 +599,7 @@ ItemSet.prototype._onAdd = ItemSet.prototype._onUpdate;
  * @param {Number[]} ids
  * @protected
  */
-ItemSet.prototype._onRemove = function _onRemove(ids) {
+ItemSet.prototype._onRemove = function(ids) {
   var count = 0;
   var me = this;
   ids.forEach(function (id) {
@@ -622,7 +622,7 @@ ItemSet.prototype._onRemove = function _onRemove(ids) {
  * Update the order of item in all groups
  * @private
  */
-ItemSet.prototype._order = function _order() {
+ItemSet.prototype._order = function() {
   // reorder the items in all groups
   // TODO: optimization: only reorder groups affected by the changed items
   util.forEach(this.groups, function (group) {
@@ -635,7 +635,7 @@ ItemSet.prototype._order = function _order() {
  * @param {Number[]} ids
  * @private
  */
-ItemSet.prototype._onUpdateGroups = function _onUpdateGroups(ids) {
+ItemSet.prototype._onUpdateGroups = function(ids) {
   this._onAddGroups(ids);
 };
 
@@ -644,7 +644,7 @@ ItemSet.prototype._onUpdateGroups = function _onUpdateGroups(ids) {
  * @param {Number[]} ids
  * @private
  */
-ItemSet.prototype._onAddGroups = function _onAddGroups(ids) {
+ItemSet.prototype._onAddGroups = function(ids) {
   var me = this;
 
   ids.forEach(function (id) {
@@ -692,7 +692,7 @@ ItemSet.prototype._onAddGroups = function _onAddGroups(ids) {
  * @param {Number[]} ids
  * @private
  */
-ItemSet.prototype._onRemoveGroups = function _onRemoveGroups(ids) {
+ItemSet.prototype._onRemoveGroups = function(ids) {
   var groups = this.groups;
   ids.forEach(function (id) {
     var group = groups[id];
@@ -748,7 +748,7 @@ ItemSet.prototype._orderGroups = function () {
  * @param {Item} item
  * @private
  */
-ItemSet.prototype._addItem = function _addItem(item) {
+ItemSet.prototype._addItem = function(item) {
   this.items[item.id] = item;
 
   // add to group
@@ -763,7 +763,7 @@ ItemSet.prototype._addItem = function _addItem(item) {
  * @param {Object} itemData
  * @private
  */
-ItemSet.prototype._updateItem = function _updateItem(item, itemData) {
+ItemSet.prototype._updateItem = function(item, itemData) {
   var oldGroupId = item.data.group;
 
   item.data = itemData;
@@ -788,7 +788,7 @@ ItemSet.prototype._updateItem = function _updateItem(item, itemData) {
  * @param {Item} item
  * @private
  */
-ItemSet.prototype._removeItem = function _removeItem(item) {
+ItemSet.prototype._removeItem = function(item) {
   // remove from DOM
   item.hide();
 
@@ -811,7 +811,7 @@ ItemSet.prototype._removeItem = function _removeItem(item) {
  * @returns {Array}
  * @private
  */
-ItemSet.prototype._constructByEndArray = function _constructByEndArray(array) {
+ItemSet.prototype._constructByEndArray = function(array) {
   var endArray = [];
 
   for (var i = 0; i < array.length; i++) {
@@ -1145,7 +1145,7 @@ ItemSet.prototype._onMultiSelectItem = function (event) {
  * @param {Event} event
  * @return {Item | null} item
  */
-ItemSet.itemFromTarget = function itemFromTarget (event) {
+ItemSet.itemFromTarget = function(event) {
   var target = event.target;
   while (target) {
     if (target.hasOwnProperty('timeline-item')) {
@@ -1163,7 +1163,7 @@ ItemSet.itemFromTarget = function itemFromTarget (event) {
  * @param {Event} event
  * @return {Group | null} group
  */
-ItemSet.groupFromTarget = function groupFromTarget (event) {
+ItemSet.groupFromTarget = function(event) {
   var target = event.target;
   while (target) {
     if (target.hasOwnProperty('timeline-group')) {
@@ -1181,7 +1181,7 @@ ItemSet.groupFromTarget = function groupFromTarget (event) {
  * @param {Event} event
  * @return {ItemSet | null} item
  */
-ItemSet.itemSetFromTarget = function itemSetFromTarget (event) {
+ItemSet.itemSetFromTarget = function(event) {
   var target = event.target;
   while (target) {
     if (target.hasOwnProperty('timeline-itemset')) {
@@ -1198,7 +1198,7 @@ ItemSet.itemSetFromTarget = function itemSetFromTarget (event) {
  * @returns {null | DataSet} dataset
  * @private
  */
-ItemSet.prototype._myDataSet = function _myDataSet() {
+ItemSet.prototype._myDataSet = function() {
   // find the root DataSet
   var dataset = this.itemsData;
   while (dataset instanceof DataView) {
diff --git a/src/timeline/component/TimeAxis.js b/src/timeline/component/TimeAxis.js
index 1c991a23..e459b70b 100644
--- a/src/timeline/component/TimeAxis.js
+++ b/src/timeline/component/TimeAxis.js
@@ -29,7 +29,7 @@ function TimeAxis (timeline, options) {
     lineTop: 0
   };
 
-  this.options = options || {};
+  this.options = Object.create(options) || {};
   this.defaultOptions = {
     orientation: 'bottom',  // supported: 'top', 'bottom'
     // TODO: implement timeaxis orientations 'left' and 'right'
@@ -58,7 +58,7 @@ TimeAxis.prototype.setOptions = Component.prototype.setOptions;
 /**
  * Create the HTML DOM for the TimeAxis
  */
-TimeAxis.prototype._create = function _create() {
+TimeAxis.prototype._create = function() {
   this.dom.foreground = document.createElement('div');
   this.dom.background = document.createElement('div');
 
@@ -376,6 +376,6 @@ TimeAxis.prototype._calculateCharSize = function () {
  * @param {Date} date   the date to be snapped.
  * @return {Date} snappedDate
  */
-TimeAxis.prototype.snap = function snap (date) {
+TimeAxis.prototype.snap = function(date) {
   return this.step.snap(date);
 };
diff --git a/src/timeline/component/item/Item.js b/src/timeline/component/item/Item.js
index 8c5b8f97..2522b49c 100644
--- a/src/timeline/component/item/Item.js
+++ b/src/timeline/component/item/Item.js
@@ -27,7 +27,7 @@ function Item (data, options, defaultOptions) {
 /**
  * Select current item
  */
-Item.prototype.select = function select() {
+Item.prototype.select = function() {
   this.selected = true;
   if (this.displayed) this.redraw();
 };
@@ -35,7 +35,7 @@ Item.prototype.select = function select() {
 /**
  * Unselect current item
  */
-Item.prototype.unselect = function unselect() {
+Item.prototype.unselect = function() {
   this.selected = false;
   if (this.displayed) this.redraw();
 };
@@ -44,7 +44,7 @@ Item.prototype.unselect = function unselect() {
  * Set a parent for the item
  * @param {ItemSet | Group} parent
  */
-Item.prototype.setParent = function setParent(parent) {
+Item.prototype.setParent = function(parent) {
   if (this.displayed) {
     this.hide();
     this.parent = parent;
@@ -62,7 +62,7 @@ Item.prototype.setParent = function setParent(parent) {
  * @returns {{start: Number, end: Number}} range with a timestamp for start and end
  * @returns {boolean} True if visible
  */
-Item.prototype.isVisible = function isVisible (range) {
+Item.prototype.isVisible = function(range) {
   // Should be implemented by Item implementations
   return false;
 };
@@ -71,7 +71,7 @@ Item.prototype.isVisible = function isVisible (range) {
  * Show the Item in the DOM (when not already visible)
  * @return {Boolean} changed
  */
-Item.prototype.show = function show() {
+Item.prototype.show = function() {
   return false;
 };
 
@@ -79,28 +79,28 @@ Item.prototype.show = function show() {
  * Hide the Item from the DOM (when visible)
  * @return {Boolean} changed
  */
-Item.prototype.hide = function hide() {
+Item.prototype.hide = function() {
   return false;
 };
 
 /**
  * Repaint the item
  */
-Item.prototype.redraw = function redraw() {
+Item.prototype.redraw = function() {
   // should be implemented by the item
 };
 
 /**
  * Reposition the Item horizontally
  */
-Item.prototype.repositionX = function repositionX() {
+Item.prototype.repositionX = function() {
   // should be implemented by the item
 };
 
 /**
  * Reposition the Item vertically
  */
-Item.prototype.repositionY = function repositionY() {
+Item.prototype.repositionY = function() {
   // should be implemented by the item
 };
 
diff --git a/src/timeline/component/item/ItemBox.js b/src/timeline/component/item/ItemBox.js
index 2258878b..0ef92303 100644
--- a/src/timeline/component/item/ItemBox.js
+++ b/src/timeline/component/item/ItemBox.js
@@ -36,7 +36,7 @@ ItemBox.prototype = new Item (null);
  * @returns {{start: Number, end: Number}} range with a timestamp for start and end
  * @returns {boolean} True if visible
  */
-ItemBox.prototype.isVisible = function isVisible (range) {
+ItemBox.prototype.isVisible = function(range) {
   // determine visibility
   // TODO: account for the real width of the item. Right now we just add 1/4 to the window
   var interval = (range.end - range.start) / 4;
@@ -46,7 +46,7 @@ ItemBox.prototype.isVisible = function isVisible (range) {
 /**
  * Repaint the item
  */
-ItemBox.prototype.redraw = function redraw() {
+ItemBox.prototype.redraw = function() {
   var dom = this.dom;
   if (!dom) {
     // create DOM
@@ -141,7 +141,7 @@ ItemBox.prototype.redraw = function redraw() {
  * Show the item in the DOM (when not already displayed). The items DOM will
  * be created when needed.
  */
-ItemBox.prototype.show = function show() {
+ItemBox.prototype.show = function() {
   if (!this.displayed) {
     this.redraw();
   }
@@ -150,7 +150,7 @@ ItemBox.prototype.show = function show() {
 /**
  * Hide the item from the DOM (when visible)
  */
-ItemBox.prototype.hide = function hide() {
+ItemBox.prototype.hide = function() {
   if (this.displayed) {
     var dom = this.dom;
 
@@ -169,7 +169,7 @@ ItemBox.prototype.hide = function hide() {
  * Reposition the item horizontally
  * @Override
  */
-ItemBox.prototype.repositionX = function repositionX() {
+ItemBox.prototype.repositionX = function() {
   var start = this.defaultOptions.toScreen(this.data.start),
       align = this.options.align || this.defaultOptions.align,
       left,
@@ -203,7 +203,7 @@ ItemBox.prototype.repositionX = function repositionX() {
  * Reposition the item vertically
  * @Override
  */
-ItemBox.prototype.repositionY = function repositionY () {
+ItemBox.prototype.repositionY = function() {
   var orientation = this.options.orientation || this.defaultOptions.orientation,
       box = this.dom.box,
       line = this.dom.line,
diff --git a/src/timeline/component/item/ItemPoint.js b/src/timeline/component/item/ItemPoint.js
index 6a6d39ff..7c290cdd 100644
--- a/src/timeline/component/item/ItemPoint.js
+++ b/src/timeline/component/item/ItemPoint.js
@@ -37,7 +37,7 @@ ItemPoint.prototype = new Item (null);
  * @returns {{start: Number, end: Number}} range with a timestamp for start and end
  * @returns {boolean} True if visible
  */
-ItemPoint.prototype.isVisible = function isVisible (range) {
+ItemPoint.prototype.isVisible = function(range) {
   // determine visibility
   // TODO: account for the real width of the item. Right now we just add 1/4 to the window
   var interval = (range.end - range.start) / 4;
@@ -47,7 +47,7 @@ ItemPoint.prototype.isVisible = function isVisible (range) {
 /**
  * Repaint the item
  */
-ItemPoint.prototype.redraw = function redraw() {
+ItemPoint.prototype.redraw = function() {
   var dom = this.dom;
   if (!dom) {
     // create DOM
@@ -137,7 +137,7 @@ ItemPoint.prototype.redraw = function redraw() {
  * Show the item in the DOM (when not already visible). The items DOM will
  * be created when needed.
  */
-ItemPoint.prototype.show = function show() {
+ItemPoint.prototype.show = function() {
   if (!this.displayed) {
     this.redraw();
   }
@@ -146,7 +146,7 @@ ItemPoint.prototype.show = function show() {
 /**
  * Hide the item from the DOM (when visible)
  */
-ItemPoint.prototype.hide = function hide() {
+ItemPoint.prototype.hide = function() {
   if (this.displayed) {
     if (this.dom.point.parentNode) {
       this.dom.point.parentNode.removeChild(this.dom.point);
@@ -163,7 +163,7 @@ ItemPoint.prototype.hide = function hide() {
  * Reposition the item horizontally
  * @Override
  */
-ItemPoint.prototype.repositionX = function repositionX() {
+ItemPoint.prototype.repositionX = function() {
   var start = this.defaultOptions.toScreen(this.data.start);
 
   this.left = start - this.props.dot.width;
@@ -176,7 +176,7 @@ ItemPoint.prototype.repositionX = function repositionX() {
  * Reposition the item vertically
  * @Override
  */
-ItemPoint.prototype.repositionY = function repositionY () {
+ItemPoint.prototype.repositionY = function() {
   var orientation = this.options.orientation || this.defaultOptions.orientation,
       point = this.dom.point;
 
diff --git a/src/timeline/component/item/ItemRange.js b/src/timeline/component/item/ItemRange.js
index bf57bf2e..751e3471 100644
--- a/src/timeline/component/item/ItemRange.js
+++ b/src/timeline/component/item/ItemRange.js
@@ -36,7 +36,7 @@ ItemRange.prototype.baseClassName = 'item range';
  * @returns {{start: Number, end: Number}} range with a timestamp for start and end
  * @returns {boolean} True if visible
  */
-ItemRange.prototype.isVisible = function isVisible (range) {
+ItemRange.prototype.isVisible = function(range) {
   // determine visibility
   return (this.data.start < range.end) && (this.data.end > range.start);
 };
@@ -44,7 +44,7 @@ ItemRange.prototype.isVisible = function isVisible (range) {
 /**
  * Repaint the item
  */
-ItemRange.prototype.redraw = function redraw() {
+ItemRange.prototype.redraw = function() {
   var dom = this.dom;
   if (!dom) {
     // create DOM
@@ -121,7 +121,7 @@ ItemRange.prototype.redraw = function redraw() {
  * Show the item in the DOM (when not already visible). The items DOM will
  * be created when needed.
  */
-ItemRange.prototype.show = function show() {
+ItemRange.prototype.show = function() {
   if (!this.displayed) {
     this.redraw();
   }
@@ -131,7 +131,7 @@ ItemRange.prototype.show = function show() {
  * Hide the item from the DOM (when visible)
  * @return {Boolean} changed
  */
-ItemRange.prototype.hide = function hide() {
+ItemRange.prototype.hide = function() {
   if (this.displayed) {
     var box = this.dom.box;
 
@@ -150,7 +150,7 @@ ItemRange.prototype.hide = function hide() {
  * Reposition the item horizontally
  * @Override
  */
-ItemRange.prototype.repositionX = function repositionX() {
+ItemRange.prototype.repositionX = function() {
   var props = this.props,
       parentWidth = this.parent.width,
       start = this.defaultOptions.toScreen(this.data.start),
@@ -188,7 +188,7 @@ ItemRange.prototype.repositionX = function repositionX() {
  * Reposition the item vertically
  * @Override
  */
-ItemRange.prototype.repositionY = function repositionY() {
+ItemRange.prototype.repositionY = function() {
   var orientation = this.options.orientation || this.defaultOptions.orientation,
       box = this.dom.box;
 
diff --git a/src/timeline/component/item/ItemRangeOverflow.js b/src/timeline/component/item/ItemRangeOverflow.js
index 6ff4a44f..f94a7ff8 100644
--- a/src/timeline/component/item/ItemRangeOverflow.js
+++ b/src/timeline/component/item/ItemRangeOverflow.js
@@ -26,7 +26,7 @@ ItemRangeOverflow.prototype.baseClassName = 'item rangeoverflow';
  * Reposition the item horizontally
  * @Override
  */
-ItemRangeOverflow.prototype.repositionX = function repositionX() {
+ItemRangeOverflow.prototype.repositionX = function() {
   var parentWidth = this.parent.width,
       start = this.defaultOptions.toScreen(this.data.start),
       end = this.defaultOptions.toScreen(this.data.end),
diff --git a/src/timeline/stack.js b/src/timeline/stack.js
index 97cee61c..b3aa5d1a 100644
--- a/src/timeline/stack.js
+++ b/src/timeline/stack.js
@@ -7,7 +7,7 @@ var stack = {};
  * Order items by their start data
  * @param {Item[]} items
  */
-stack.orderByStart = function orderByStart(items) {
+stack.orderByStart = function(items) {
   items.sort(function (a, b) {
     return a.data.start - b.data.start;
   });
@@ -18,7 +18,7 @@ stack.orderByStart = function orderByStart(items) {
  * is used.
  * @param {Item[]} items
  */
-stack.orderByEnd = function orderByEnd(items) {
+stack.orderByEnd = function(items) {
   items.sort(function (a, b) {
     var aTime = ('end' in a.data) ? a.data.end : a.data.start,
         bTime = ('end' in b.data) ? b.data.end : b.data.start;
@@ -38,7 +38,7 @@ stack.orderByEnd = function orderByEnd(items) {
  *            If true, all items will be repositioned. If false (default), only
  *            items having a top===null will be re-stacked
  */
-stack.stack = function _stack (items, margin, force) {
+stack.stack = function(items, margin, force) {
   var i, iMax;
 
   if (force) {
@@ -83,7 +83,7 @@ stack.stack = function _stack (items, margin, force) {
  * @param {{item: number, axis: number}} margin
  *            Margins between items and between items and the axis.
  */
-stack.nostack = function nostack (items, margin) {
+stack.nostack = function(items, margin) {
   var i, iMax;
 
   // reset top position of all items
@@ -104,7 +104,7 @@ stack.nostack = function nostack (items, margin) {
  *                          the requested margin.
  * @return {boolean}        true if a and b collide, else false
  */
-stack.collision = function collision (a, b, margin) {
+stack.collision = function(a, b, margin) {
   return ((a.left - margin) < (b.left + b.width) &&
       (a.left + a.width + margin) > b.left &&
       (a.top - margin) < (b.top + b.height) &&
diff --git a/src/util.js b/src/util.js
index 31b06794..48ba74de 100644
--- a/src/util.js
+++ b/src/util.js
@@ -8,7 +8,7 @@ var util = {};
  * @param {*} object
  * @return {Boolean} isNumber
  */
-util.isNumber = function isNumber(object) {
+util.isNumber = function(object) {
   return (object instanceof Number || typeof object == 'number');
 };
 
@@ -17,7 +17,7 @@ util.isNumber = function isNumber(object) {
  * @param {*} object
  * @return {Boolean} isString
  */
-util.isString = function isString(object) {
+util.isString = function(object) {
   return (object instanceof String || typeof object == 'string');
 };
 
@@ -26,7 +26,7 @@ util.isString = function isString(object) {
  * @param {Date | String} object
  * @return {Boolean} isDate
  */
-util.isDate = function isDate(object) {
+util.isDate = function(object) {
   if (object instanceof Date) {
     return true;
   }
@@ -49,7 +49,7 @@ util.isDate = function isDate(object) {
  * @param {*} object
  * @return {Boolean} isDataTable
  */
-util.isDataTable = function isDataTable(object) {
+util.isDataTable = function(object) {
   return (typeof (google) !== 'undefined') &&
       (google.visualization) &&
       (google.visualization.DataTable) &&
@@ -61,7 +61,7 @@ util.isDataTable = function isDataTable(object) {
  * source: http://stackoverflow.com/a/105074/1262753
  * @return {String} uuid
  */
-util.randomUUID = function randomUUID () {
+util.randomUUID = function() {
   var S4 = function () {
     return Math.floor(
         Math.random() * 0x10000 /* 65536 */
@@ -103,7 +103,7 @@ util.extend = function (a, b) {
  * @param {Object} b
  * @returns {Object}
  */
-util.deepExtend = function deepExtend (a, b) {
+util.deepExtend = function(a, b) {
   // TODO: add support for Arrays to deepExtend
   if (Array.isArray(b)) {
     throw new TypeError('Arrays are not supported by deepExtend');
@@ -116,7 +116,7 @@ util.deepExtend = function deepExtend (a, b) {
           a[prop] = {};
         }
         if (a[prop].constructor === Object) {
-          deepExtend(a[prop], b[prop]);
+          util.deepExtend(a[prop], b[prop]);
         }
         else {
           a[prop] = b[prop];
@@ -157,7 +157,7 @@ util.equalArray = function (a, b) {
  * @return {*} object
  * @throws Error
  */
-util.convert = function convert(object, type) {
+util.convert = function(object, type) {
   var match;
 
   if (object === undefined) {
@@ -307,7 +307,7 @@ var ASPDateRegex = /^\/?Date\((\-?\d+)/i;
  * @param {*} object
  * @return {String} type
  */
-util.getType = function getType(object) {
+util.getType = function(object) {
   var type = typeof object;
 
   if (type == 'object') {
@@ -350,7 +350,7 @@ util.getType = function getType(object) {
  * @return {number} left        The absolute left position of this element
  *                              in the browser page.
  */
-util.getAbsoluteLeft = function getAbsoluteLeft (elem) {
+util.getAbsoluteLeft = function(elem) {
   var doc = document.documentElement;
   var body = document.body;
 
@@ -370,7 +370,7 @@ util.getAbsoluteLeft = function getAbsoluteLeft (elem) {
  * @return {number} top        The absolute top position of this element
  *                              in the browser page.
  */
-util.getAbsoluteTop = function getAbsoluteTop (elem) {
+util.getAbsoluteTop = function(elem) {
   var doc = document.documentElement;
   var body = document.body;
 
@@ -389,7 +389,7 @@ util.getAbsoluteTop = function getAbsoluteTop (elem) {
  * @param {Event} event
  * @return {Number} pageY
  */
-util.getPageY = function getPageY (event) {
+util.getPageY = function(event) {
   if ('pageY' in event) {
     return event.pageY;
   }
@@ -415,7 +415,7 @@ util.getPageY = function getPageY (event) {
  * @param {Event} event
  * @return {Number} pageX
  */
-util.getPageX = function getPageX (event) {
+util.getPageX = function(event) {
   if ('pageY' in event) {
     return event.pageX;
   }
@@ -441,7 +441,7 @@ util.getPageX = function getPageX (event) {
  * @param {Element} elem
  * @param {String} className
  */
-util.addClassName = function addClassName(elem, className) {
+util.addClassName = function(elem, className) {
   var classes = elem.className.split(' ');
   if (classes.indexOf(className) == -1) {
     classes.push(className); // add the class to the array
@@ -454,7 +454,7 @@ util.addClassName = function addClassName(elem, className) {
  * @param {Element} elem
  * @param {String} className
  */
-util.removeClassName = function removeClassname(elem, className) {
+util.removeClassName = function(elem, className) {
   var classes = elem.className.split(' ');
   var index = classes.indexOf(className);
   if (index != -1) {
@@ -472,7 +472,7 @@ util.removeClassName = function removeClassname(elem, className) {
  *                                  the object or array with three parameters:
  *                                  callback(value, index, object)
  */
-util.forEach = function forEach (object, callback) {
+util.forEach = function(object, callback) {
   var i,
       len;
   if (object instanceof Array) {
@@ -497,7 +497,7 @@ util.forEach = function forEach (object, callback) {
  * @param {Object} object
  * @param {Array} array
  */
-util.toArray = function toArray(object) {
+util.toArray = function(object) {
   var array = [];
 
   for (var prop in object) {
@@ -514,7 +514,7 @@ util.toArray = function toArray(object) {
  * @param {*} value
  * @return {Boolean} changed
  */
-util.updateProperty = function updateProperty (object, key, value) {
+util.updateProperty = function(object, key, value) {
   if (object[key] !== value) {
     object[key] = value;
     return true;
@@ -532,7 +532,7 @@ util.updateProperty = function updateProperty (object, key, value) {
  * @param {function}    listener   The callback function to be executed
  * @param {boolean}     [useCapture]
  */
-util.addEventListener = function addEventListener(element, action, listener, useCapture) {
+util.addEventListener = function(element, action, listener, useCapture) {
   if (element.addEventListener) {
     if (useCapture === undefined)
       useCapture = false;
@@ -554,7 +554,7 @@ util.addEventListener = function addEventListener(element, action, listener, use
  * @param {function}    listener        The listener function
  * @param {boolean}     [useCapture]
  */
-util.removeEventListener = function removeEventListener(element, action, listener, useCapture) {
+util.removeEventListener = function(element, action, listener, useCapture) {
   if (element.removeEventListener) {
     // non-IE browsers
     if (useCapture === undefined)
@@ -577,7 +577,7 @@ util.removeEventListener = function removeEventListener(element, action, listene
  * @param {Event} event
  * @return {Element} target element
  */
-util.getTarget = function getTarget(event) {
+util.getTarget = function(event) {
   // code from http://www.quirksmode.org/js/events_properties.html
   if (!event) {
     event = window.event;
@@ -605,7 +605,7 @@ util.getTarget = function getTarget(event) {
  * @param {Element} element
  * @param {Event} event
  */
-util.fakeGesture = function fakeGesture (element, event) {
+util.fakeGesture = function(element, event) {
   var eventType = null;
 
   // for hammer.js 1.0.5
@@ -721,7 +721,7 @@ util.option.asElement = function (value, defaultValue) {
 
 
 
-util.GiveDec = function GiveDec(Hex) {
+util.GiveDec = function(Hex) {
   var Value;
 
   if (Hex == "A")
@@ -742,7 +742,7 @@ util.GiveDec = function GiveDec(Hex) {
   return Value;
 };
 
-util.GiveHex = function GiveHex(Dec) {
+util.GiveHex = function(Dec) {
   var Value;
 
   if(Dec == 10)
@@ -846,7 +846,7 @@ util.parseColor = function(color) {
  * @param {String} hex
  * @returns {{r: *, g: *, b: *}}
  */
-util.hexToRGB = function hexToRGB(hex) {
+util.hexToRGB = function(hex) {
   hex = hex.replace("#","").toUpperCase();
 
   var a = util.GiveDec(hex.substring(0, 1));
@@ -863,7 +863,7 @@ util.hexToRGB = function hexToRGB(hex) {
   return {r:r,g:g,b:b};
 };
 
-util.RGBToHex = function RGBToHex(red,green,blue) {
+util.RGBToHex = function(red,green,blue) {
   var a = util.GiveHex(Math.floor(red / 16));
   var b = util.GiveHex(red % 16);
   var c = util.GiveHex(Math.floor(green / 16));
@@ -885,7 +885,7 @@ util.RGBToHex = function RGBToHex(red,green,blue) {
  * @returns {*}
  * @constructor
  */
-util.RGBToHSV = function  RGBToHSV (red,green,blue) {
+util.RGBToHSV = function(red,green,blue) {
   red=red/255; green=green/255; blue=blue/255;
   var minRGB = Math.min(red,Math.min(green,blue));
   var maxRGB = Math.max(red,Math.max(green,blue));
@@ -913,7 +913,7 @@ util.RGBToHSV = function  RGBToHSV (red,green,blue) {
  * @returns {{r: number, g: number, b: number}}
  * @constructor
  */
-util.HSVToRGB = function HSVToRGB(h, s, v) {
+util.HSVToRGB = function(h, s, v) {
   var r, g, b;
 
   var i = Math.floor(h * 6);
@@ -934,22 +934,22 @@ util.HSVToRGB = function HSVToRGB(h, s, v) {
   return {r:Math.floor(r * 255), g:Math.floor(g * 255), b:Math.floor(b * 255) };
 };
 
-util.HSVToHex = function HSVToHex(h, s, v) {
+util.HSVToHex = function(h, s, v) {
   var rgb = util.HSVToRGB(h, s, v);
   return util.RGBToHex(rgb.r, rgb.g, rgb.b);
 };
 
-util.hexToHSV = function hexToHSV(hex) {
+util.hexToHSV = function(hex) {
   var rgb = util.hexToRGB(hex);
   return util.RGBToHSV(rgb.r, rgb.g, rgb.b);
 };
 
-util.isValidHex = function isValidHex(hex) {
+util.isValidHex = function(hex) {
   var isOk = /(^#[0-9A-F]{6}$)|(^#[0-9A-F]{3}$)/i.test(hex);
   return isOk;
 };
 
-util.copyObject = function copyObject(objectFrom, objectTo) {
+util.copyObject = function(objectFrom, objectTo) {
   for (var i in objectFrom) {
     if (objectFrom.hasOwnProperty(i)) {
       if (typeof objectFrom[i] == "object") {