CARVIEW |
Pointer Events Specification
W3C Member Submission 7 September 2012
Document Status Update 2013-05-09: The Pointer Events Working Group has published a document, based on this Member Submission, that is intended to become a W3C Recommendation.
- This version:
- https://www.w3.org/submissions/2012/SUBM-pointer-events-20120907/
- Latest published version:
- https://www.w3.org/submissions/pointer-events/
- Editor:
- Jacob Rossi, Microsoft Corporation
Adrian Bateman, Microsoft Corporation
Copyright© 2012 Microsoft Corporation
This document is available under the W3C Document License. See the W3C Intellectual Rights Notice and Legal Disclaimers for additional information.
Abstract
This document defines events and related interfaces for handling hardware agnostic pointer input from devices like a mouse, pen, or touchscreen. For compatibility with existing mouse-based content, this specification also describes a mapping to fire [DOM-LEVEL-3-EVENTS] Mouse Events for pointer device types other than mouse.
Status of This Document
This section describes the status of this document at the time of its publication. Other documents may supersede this document. A list of current W3C publications can be found in the W3C technical reports index at https://www.w3.org/TR/.
This document was published by the Microsoft Corporation as a Member Submission.
By publishing this document, W3C acknowledges that the Submitting Members have made a formal Submission request to W3C for discussion. Publication of this document by W3C indicates no endorsement of its content by W3C, nor that W3C has, is, or will be allocating any resources to the issues addressed by it. This document is not the product of a chartered W3C group, but is published as potential input to the W3C Process. A W3C Team Comment has been published in conjunction with this Member Submission. Publication of acknowledged Member Submissions at the W3C site is one of the benefits of W3C Membership. Please consult the requirements associated with Member Submissions of section 3.3 of the W3C Patent Policy. Please consult the complete list of acknowledged W3C Member Submissions.
Table of Contents
- 1. Introduction
- 2. Conformance
- 3. Pointer Events and Interfaces
- 4. Extensions to the
Element
interface - 5. Extensions to the
Navigator
interface - 6. Declaring candidate regions for default touch behaviors
- 7. Compatibility Mapping with Mouse Events
- 8. Examples
- 9. Glossary
- A. Acknowledgements
- B. References
1. Introduction
This section is non-normative.
Today, most [HTML5] content is used with and/or designed for mouse input. Those that handle input in a custom manner typically code to [DOM-LEVEL-3-EVENTS] Mouse Events. Newer computing devices today, however, incorporate other forms of input, like touchscreens or pen input. Event types have been proposed for handling each of these forms of input individually. However, that approach requires a step function in opportunity cost to authors when adding support for a new input type. This often creates a compatibility problem when content is written with only one device type in mind. Additionally, for compatibility with existing mouse-based content, most user agents fire Mouse Events for all input types. This makes it ambiguous whether a Mouse Event represents an actual mouse device or is being produced from another input type for compatibility, which makes it hard to code to both device types simultaneously.
To reduce the cost of coding to multiple input types and also to help with the above described ambiguity with Mouse Events, this specifications defines a more abstract form of input, called a pointer. A pointer can be any point of contact on the screen made by a mouse cursor, pen, touch (including multi-touch), or other pointing input device. This model makes it easy to write sites and applications that work well no matter what hardware the user has. For scenarios when device-specific handling is desired, this specification also defines properties for inspecting the device type which produced the event. The primary goal is to provide a single set of events and interfaces that allow for easy authoring for cross-device pointer input while still allowing for device-specific handling when necessary.

The events for handling generic pointer input look a lot like those for mouse: pointerdown, pointermove, pointerup, pointerover, pointerout, etc. This facilitates easy content migration from Mouse Events to Pointer Events. Pointer Events provide all the usual properties present in Mouse Events (client coordinates, target element, button states, etc.) in addition to new properties for other forms of input: pressure, contact geometry, tilt, etc. So authors can easily code to Pointer Events and their content just works no matter what input hardware is being used.
2. Conformance
As well as sections marked as non-normative, all authoring guidelines, diagrams, examples, and notes in this specification are non-normative. Everything else in this specification is normative.
The key words must, must not, required, should, should not, recommended, may, and optional in this specification are to be interpreted as described in [RFC2119].
Implementations that use ECMAScript to expose the APIs defined in this specification must implement them in a manner consistent with the ECMAScript Bindings defined in the Web IDL specification [WEBIDL].
3. Pointer Events and Interfaces
3.1 PointerEvent
Interface
[Constructor]
interface PointerEvent : MouseEvent {
const unsigned short POINTER_TYPE_UNAVAILABLE = 0x00000001;
const unsigned short POINTER_TYPE_TOUCH = 0x00000002;
const unsigned short POINTER_TYPE_PEN = 0x00000003;
const unsigned short POINTER_TYPE_MOUSE = 0x00000004;
readonly attribute long pointerId;
readonly attribute long width;
readonly attribute long height;
readonly attribute float pressure;
readonly attribute long tiltX;
readonly attribute long tiltY;
readonly attribute long pointerType;
readonly attribute unsigned long long hwTimestamp;
readonly attribute boolean isPrimary;
};
Attributes
pointerId
of type long, readonly-
A unique identifier for the pointer causing the event. This identifier must be unique from all other active pointers at the time. A user agent may recycle previously retired values for
pointerId
from previous active pointers, if necessary.If the device producing the event is a mouse, then the
pointerId
must be 1. Device types other than mouse must not have apointerId
of 1. width
of type long, readonly- The width (magnitude on the X axis), in physical screen pixels, of the contact geometry of the pointer. This value may be updated on each event for a given pointer. For devices which have a contact geometry but the actual geometry is not reported by the hardware, a default value may be provided by the user agent to approximate the geometry typical of that pointer type. Otherwise, the value must be 0.
height
of type long, readonly-
The height (magnitude on the Y axis), in physical screen pixels, of the contact geometry of the pointer. This value may be updated on each event for a given pointer. For devices which have a contact geometry but the actual geometry is not reported by the hardware, a default value may be provided by the user agent to approximate the geometry typical of that pointer type. Otherwise, the value must be 0.
Issue 1Physical screen pixels may be ineffective. For example, the physical size of the contact cannot be surmised due to varying pixel densities of devices (which are not always reported by the user agent). Further, it is generally impossible or difficult to correlate this back to CSS pixels in the document (which often are not at a fixed ratio to screen pixels due to zoom).
pressure
of type float, readonly- The normalized pressure of the pointer input in the range of [0,1], where 0 and 1 represent the minimum and maximum pressure the hardware is capable of detecting, respectively. For hardware that does not support pressure, including but not limited to mouse, the value must be 0.
tiltX
of type long, readonly-
The plane angle (in degrees, in the range of [-90,90]) between the Y-Z plane and the plane containing both the transducer (e.g. pen stylus) axis and the Y axis. A positive
tiltX
is to the right.tiltX
can be used along withtiltY
to represent the tilt away from the normal of a transducer with the digitzer. For devices that do not report tilt, the value must be 0.Fig. 2 Positive tiltX. tiltY
of type long, readonly-
The plane angle (in degrees, in the range of [-90,90]) between the X-Z plane and the plane containing both the transducer (e.g. pen stylus) axis and the X axis. A positive
tiltY
is towards the user.tiltY
can be used along withtiltX
to represent the tilt away from the normal of a transducer with the digitzer. For devices that do not report tilt, the value must be 0.Fig. 3 Negative tiltY. pointerType
of type long, readonly-
Indicates the device type that caused the event (mouse, pen, touch, etc.). Possible values are defined as constants on the
PointerEvent
interface.Issue 2Should this be a string rather than enumerated constants? What about extensibility? hwTimestamp
of type unsigned long long, readonly-
A timestamp, in microseconds, of the pointer event as reported by hardware. The origin time (e.g.
hwTimestamp
equals 0) is hardware and/or operating system dependent. If the hardware does not provide a high resolution timestamp, then the value must be 0.NoteThis value is typically determined by using the hardware's high-resolution performance counter. isPrimary
of type boolean, readonly- Indicates if the pointer represents the primary pointer.
Constants
POINTER_TYPE_UNAVAILABLE
of type unsigned short-
Value for
pointerType
when the device type being used cannot be detected by the user agent. POINTER_TYPE_TOUCH
of type unsigned short-
Value for
pointerType
when the device being used can be detected and is a touchscreen. POINTER_TYPE_PEN
of type unsigned short-
Value for
pointerType
when the device being used can be detected and is a pen stylus. POINTER_TYPE_MOUSE
of type unsigned short-
Value for
pointerType
when the device being used can be detected and is a mouse.
3.1.1 Button States
3.1.1.1 Chorded Button Interactions
Some pointer devices, such as mouse or pen, support multiple buttons. In the [DOM-LEVEL-3-EVENTS] Mouse Event model, each button press produces a mousedown
and mouseup
event. To better abstract this hardware difference and simplify cross-device input authoring, Pointer Events do not fire overlapping pointerdown
and pointerup
events for chorded button presses (depressing an additional button while another button on the pointer device is already depressed).
Instead, chorded button presses can be detected by inspecting changes to the button
and buttons
properties. The button
and buttons
properties are inherited from the [DOM-LEVEL-3-EVENTS] MouseEvent
interface. In order to facilitate differentiating button state transitions in any pointer event (and not just pointerdown
and pointerup
), the button
property takes on a new value when no mouse buttons are depressed:
Device Button State | button | buttons |
---|---|---|
Mouse move with no buttons pressed | -1 | 0 |
Left Mouse, Touch Contact, Pen contact (with no modifier buttons pressed) | 0 | 1 |
Middle Mouse | 1 | 4 |
Right Mouse, Pen contact with barrel button pressed | 2 | 2 |
X1 (back) Mouse | 3 | 8 |
X2 (forward) Mouse | 4 | 16 |
3.1.2 The Primary Pointer
In a multi-pointer (e.g. multi-touch) scenario, the primary pointer is used to identify a master pointer amongst the set of active pointers. This pointer is the one that will produce compatibility mouse events. It is also useful when single-pointer interaction is desired by an author.
The primary pointer is indicated on events by a value of true
for the isPrimary
property.
3.1.2.1 Determining the primary pointer
- The pointer represents a mouse device.
- The pointer represents a primary touch input.
- The pointer represents a primary pen input.
- primary touch input
- A pointer representing touch input is considered the primary touch input if its
pointerdown
event was dispatched when no other active pointers representing touch input existed. - primary pen input
- A pointer representing pen input is considered the primary pen input if its
pointerdown
event was dispatched when no other active pointers representing pen input existed.
false
for isPrimary
.3.2 Pointer Event Types
3.2.1 List of Pointer Events
This section is non-normative.
The following table provides a summary of the event types defined in this specification.
Event Type | Sync/Async | Bubbles | Cancellable | Trusted proximal event target types | Event object interface | Default Action |
---|---|---|---|---|---|---|
pointerdown |
Sync | Yes | Yes | Document , Element |
PointerEvent |
Varies: when the pointer is primary, all default actions of the mousedown event |
pointerup |
Sync | Yes | Yes | Document , Element |
PointerEvent |
Varies: when the pointer is primary, all default actions of mouseup |
pointercancel |
Sync | Yes | Yes | Document , Element |
PointerEvent |
None |
pointermove |
Sync | Yes | Yes | Document , Element |
PointerEvent |
Varies: when the pointer is primary, all default actions of mousemove |
pointerover |
Sync | Yes | Yes | Document , Element |
PointerEvent |
Varies: when the pointer is primary, all default actions of mouseover |
pointerout |
Sync | Yes | Yes | Document , Element |
PointerEvent |
Varies: when the pointer is primary, all default actions of mouseout |
gotpointercapture |
Async | Yes | No | Element |
PointerEvent |
None |
lostpointercapture |
Async | Yes | No | Element |
PointerEvent |
None |
3.2.2 The pointerdown
event
A user agent must dispatch this event when a pointer enters the active buttons state. For mouse, this is when the the device transitions from no buttons depressed to at least one button depressed. For touch, this is when physical contact is made with the digitizer. For pen, this is when the stylus makes physical contact with the digitizer.
For input devices that do not support hover, a user agent must also fire a pointerover
event proceeding the pointerdown
event.
pointerdown
and pointerup
are dispatched differently than mousedown
and mouseup
. See chorded buttons for more information.3.2.3 The pointerup
event
For input devices that do not support hover, a user agent must also fire a pointerout
event after firing the pointerup
event.
pointerdown
and pointerup
are dispatched differently than mousedown
and mouseup
. See chorded buttons for more information.3.2.4 The pointercancel
event
- The user agent has determined that a pointer is unlikely to continue to produce events (for example, because of a hardware event).
- After having fired the
pointerdown
event, the pointer is subsequently used to manipulate the page viewport (e.g. panning or zooming).
A user agent must also fire a pointerout
event after firing the pointercancel
event.
This section is non-normative.
Examples of scenarios in which a user agent might determine that a pointer is unlikely to continue to produce events include:
- A device's screen orientation is changed while a pointer is active.
- The user inputs a greater number of simultaneous pointers than is supported by the device.
- The user agent interprets the input as accidental (for example, the hardware supports palm rejection).
Methods for changing the device’s screen orientation, recognizing accidental input, or using a pointer to manipulate the viewport (e.g. panning or zooming) are out of scope for this specification.
3.2.5 The pointermove
event
width
and height
).3.2.6 The pointerover
event
pointerdown
event for devices that do not support hover.3.2.7 The pointerout
event
- A pointing device is moved out of the hit test boundaries of an element
- After firing the
pointerup
event for a device that does not support hover - After firing the
pointercancel
event
3.2.8 The gotpointercapture
event
setPointerCapture()
.3.2.9 The lostpointercapture
event
releasePointerCapture()
.4. Extensions to the Element
interface
partial interface Element {
void setPointerCapture (long pointerId);
void releasePointerCapture (long pointerId);
attribute EventHandler onpointerdown;
attribute EventHandler onpointermove;
attribute EventHandler onpointerup;
attribute EventHandler onpointercancel;
attribute EventHandler onpointerover;
attribute EventHandler onpointerout;
attribute EventHandler ongotpointercapture;
attribute EventHandler onlostpointercapture;
};
Attributes
onpointerdown
of type EventHandler-
The event handler IDL attribute (see [HTML5]) for the
pointerdown
event type. onpointermove
of type EventHandler-
The event handler IDL attribute (see [HTML5]) for the
pointermove
event type. onpointerup
of type EventHandler-
The event handler IDL attribute (see [HTML5]) for the
pointerup
event type. onpointercancel
of type EventHandler-
The event handler IDL attribute (see [HTML5]) for the
pointercancel
event type. onpointerover
of type EventHandler-
The event handler IDL attribute (see [HTML5]) for the
pointerover
event type. onpointerout
of type EventHandler-
The event handler IDL attribute (see [HTML5]) for the
pointerout
event type. ongotpointercapture
of type EventHandler-
The event handler IDL attribute (see [HTML5]) for the
gotpointercapture
event type. onlostpointercapture
of type EventHandler-
The event handler IDL attribute (see [HTML5]) for the
lostpointercapture
event type.
Methods
setPointerCapture
-
Sets pointer capture for the pointer identified by the argument
pointerId
to the element on which this method is invoked. Subsequent events for the pointer must always be targeted at this element.If the
pointerId
provided as the method's argument does not match any of the active pointers, then the user agent must throw aDOMException
with the nameInvalidPointerId
.Parameter Type Nullable Optional Description pointerId long
✘ ✘ Return type:void
releasePointerCapture
-
Releases pointer capture for the pointer identified by the argument
pointerId
from the element on which this method is invoked. Subsequent events for the pointer follow normal hit testing mechanisms (out of scope for this specification) for determining the event target.If the
pointerId
provided as the method's argument does not match any of the active pointers, then the user agent must throw aDOMException
with the nameInvalidPointerId
.If pointer capture has not been set for the
pointerId
provided, then this method fails silently.Parameter Type Nullable Optional Description pointerId long
✘ ✘ Return type:void
5. Extensions to the Navigator
interface
The Navigator
interface is defined in [HTML5]. This specification extends the Navigator
interface to provide device and feature detection support.
interface {
readonly attribute boolean pointerEnabled;
readonly attribute long maxTouchPoints;
};
Attributes
pointerEnabled
of type boolean, readonly- Indicates if the browser will fire pointer events for pointing input.
maxTouchPoints
of type long, readonlyThe maximum number of simultaneous touch contacts supported by the device. In the case of devices with multiple ditigizers (e.g. multiple touchscreens), the value must be the maximum of the set of maximum supported contacts by each individual digitizer.
For example, suppose a device has 3 touchscreens, which support 2, 5, and 10 simultaneous touch contacts, respectively. The value of
maxTouchPoints
is10
.
6. Declaring candidate regions for default touch behaviors
For touch input, the default action of any and all pointer events must not be a manipulation of the viewport (e.g. panning or zooming).
6.1 The touch-action
CSS property
Name: | touch-action |
---|---|
Value: | auto | none | inherit |
Initial: | auto |
Applies to: | block-level elements, SVG elements |
Inherited: | no |
Percentages: | N/A |
Media: | visual |
Computed value: | Same as specified value. |
touch-action
CSS property determines whether touch input may trigger default behavior supplied by user agent. This includes, but is not limited to, behaviors such as panning or zooming.Values have the following meanings:
- auto
- The user agent may determine the permitted touch behaviors, such as panning and zooming manipulations of the viewport, for touches that begin on the element.
- none
- Touches that begin on the element must not trigger default touch behaviors.
- inherit
- The property takes the same specified value as the property for the element's parent.
A user agent must dispatch a pointercancel
(and subsequently a pointerout
event) whenever all of the following are true:
- The user agent has determined (via methods out of scope for this specification) that touch input is to be consumed for a default touch behavior,
- a
pointerdown
event has been sent for the pointer, and - a
pointerup
orpointercancel
event (following the above mentionedpointerdown
) has not yet been sent for the pointer.
During the execution of the behavior (after sending the pointercancel
and pointerout
events), the user agent must not dispatch subsequent pointer events for the pointer.
7. Compatibility Mapping with Mouse Events
The vast majority of web content existing today codes only to Mouse Events. The following describes the algorithm for how a user agent must map generic pointer input to mouse events for compatibility with this content. Unless otherwise noted, the target of any mapped mouse event must be the same as the target for the pointer event from which it was mapped.
Authors can prevent the production of compatibility mouse events by cancelling the pointerdown
event.
This section is non-normative
The click
event is defined in [DOM-LEVEL-3-EVENTS] and is not considered a compatibility mouse event as it is typically tied to user interface activation.
In user agents that support firing click
, calling preventDefault
during a pointer event typically does not have an effect on whether click
is fired or not. Because it is not a compatibility mouse event, user agents typically fire click
for all pointing devices, including pointers that are not primary pointers.
7.1 Mapping for devices that support hover
- If the
isPrimary
property for the pointer event to be dispatched isfalse
then dispatch the pointer event and terminate these steps. - Dispatch the pointer event.
- If the pointer event dispatched was
pointerdown
and the event was cancelled, then set the PREVENT MOUSE EVENT flag. - If the pointer event dispatched was
pointerover
,- dispatch a
mouseover
event, and - if the pointer has been moved onto the boundaries of an element or one of its descendents then dispatch a
mouseenter
event.
- dispatch a
- If the pointer event dispatched was
pointerout
- dispatch a
mouseout
event, and - if the pointer has been moved out of the boundaries of an element and all of its descendents then dispatch a
mouseleave
event.
- dispatch a
- If the PREVENT MOUSE EVENT flag is not set and the pointer event dispatched was:
pointerdown
, then dispatch amousedown
event.pointermove
, then dispatch amousemove
event.pointerup
, then dispatch amouseup
event.pointercancel
, then dispatch amouseup
event at thewindow
.
- If the pointer event dispatched was
pointerup
orpointercancel
, clear the PREVENT MOUSE EVENT flag.
mouseover
and mouseout
events are never prevented (even if the pointer is down).7.2 Mapping for devices that do not support hover
- The input can hover independently of activation (e.g. moving a mouse cursor without any buttons pressed)
- The input will likely produce the
mousemove
event on an element before clicking it
- If the
isPrimary
property for the pointer event to be dispatched isfalse
then dispatch the pointer event and terminate these steps. - If the pointer event to be dispatched is
pointerover
and thepointerdown
event has not yet been dispatched for this pointer, then dispatch amousemove
event. - Dispatch the pointer event.
- If the pointer event dispatched was
pointerdown
and the event was cancelled, then set the PREVENT MOUSE EVENT flag. - If the pointer event dispatched was
pointerover
,- dispatch a
mouseover
event, and - if the pointer has been moved onto the boundaries of an element or one of its descendents then dispatch a
mouseenter
event.
- dispatch a
- If the pointer event dispatched was
pointerout
- dispatch a
mouseout
event, and - if the pointer has been moved out of the boundaries of an element and all of its descendents then dispatch a
mouseleave
event.
- dispatch a
- If the PREVENT MOUSE EVENT flag is not set and the pointer event dispatched was:
pointerdown
, then dispatch amousedown
event.pointermove
, then dispatch amousemove
event.pointerup
, then dispatch amouseup
event.pointercancel
, then dispatch amouseup
event at thewindow
.
- If the pointer event dispatched was
pointerup
orpointercancel
, clear the PREVENT MOUSE EVENT flag.
mouseover
and mouseout
events are never prevented (even if the pointer is down).8. Examples
This section is non-normative.
The following are example author code that demonstrates how the APIs in this specification might be used.
<style> /* Disable intrinsic user agent touch behaviors (such as panning or zooming) so that all events are given to the application instead. */ html { touch-action: none; } </style> <canvas id="drawSurface" width="500px" height="500px" style="border:1px solid black;"></canvas> <script type='text/javascript'> window.addEventListener('load', function() { var canvas = document.getElementById("drawSurface"), context = canvas.getContext("2d"); if (window.navigator.pointerEnabled) { canvas.addEventListener("pointermove", paint, false); if(window.navigator.maxTouchPoints>1) alert("Your user agent and hardware support multi-touch!"); } else { //Provide fallback for user agents that do not support Pointer Events canvas.addEventListener("mousemove", paint, false); } function paint(event) { if(event.buttons>0) context.fillRect(event.clientX, event.clientY, 5, 5); } }); </script>
window.addEventListener("pointerdown", detectInputType, false); function detectInputType(event) { switch(event.pointerType) { case event.POINTER_TYPE_MOUSE: alert("You used a mouse!"); break; case event.POINTER_TYPE_PEN: alert("You used a pen stylus!"); break; case event.POINTER_TYPE_TOUCH: alert("You used touch!"); break; case event.POINTER_TYPE_UNAVAILABLE: alert("Not sure what device was used!"); break; } }
<div style="position:absolute; top:0px; left:0px; width:100px;height:100px;"></div> <script> window.addEventListener("pointerdown", checkPointerSize, false); function checkPointerSize(event) { event.target.style.width = event.width + "px"; event.target.style.height = event.height + "px"; } </script>
9. Glossary
- active buttons state
- The condition when a pointer has a non-zero value for the
buttons
property. For mouse, this is when the the device has at least one button depressed. For touch, this is when there is physical contact with the digitizer. For pen, this is when the pen has physical contact with the digitizer. - active pointer
- Any touch contact, pen stylus, mouse cursor, or other pointer that can produce events. If it is possible for a given pointer (identified by a unique
pointerId
) to produce additional events, then that pointer is still considered active. Examples:- A mouse connected to the device is always active.
- A touch contact on the screen is considered active.
- If a touch contact or pen stylus is lifted beyond the range of the digitizer, then it is no longer considered active.
NoteIn some platforms, the set of active pointers includes all pointer input to the device, including any that are not targeted at the user agent (e.g. another application). - cancelled event
- An event whose default action was prevented by means of
preventDefault()
, returningfalse
in an event handler, or other means as defined by [DOM-LEVEL-3-EVENTS] and [HTML5]. - contact geometry
- The bounding box of an input (most commonly, touch) on a digitizer. This typically refers to devices with coarser pointer input resolution than a single pixel. Some devices do not report this data at all.
- digitizer
- A type of input sensing device in which a surface can detect input which is in contact and/or in close proximity. Most commonly, this is the surface that sense input from touch contact or a pen stylus.
- pointer
- A hardware agnostic representation of input devices that can target a specific coordinate (or set of coordinates) on a screen, such as a mouse, pen, or touch contact.
- user agent
- A program, such as a browser or content authoring tool, normally running on a client machine, which acts on a user's behalf in retrieving, interpreting, executing, presenting, or creating content.
A. Acknowledgements
Many thanks to lots of people for their proposals and recommendations, some of which are incorporated into this document.
Special thanks to those that helped pioneer the first edition of this model, including especially: Charu Chandiram, Peter Freiling, Nathan Furtwangler, Thomas Olsen, Matt Rakow, Ramu Ramanathan, Justin Rogers, Jacob Rossi, Reed Townsend, Steve Wright.
B. References
B.1 Normative references
- [DOM-LEVEL-3-EVENTS]
- Travis Leithead; Jacob Rossi; Doug Schepers; Björn Höhrmann; Philippe Le Hégaret; Tom Pixley. Document Object Model (DOM) Level 3 Events Specification. 14 June 2012. W3C Working Draft. (Work in progress.) URL: https://www.w3.org/TR/2012/WD-DOM-Level-3-Events-20120614/
- [HTML5]
- Ian Hickson; David Hyatt. HTML5. 29 March 2012. W3C Working Draft. (Work in progress.) URL: https://www.w3.org/TR/html5
- [RFC2119]
- S. Bradner. Key words for use in RFCs to Indicate Requirement Levels. March 1997. Internet RFC 2119. URL: https://www.ietf.org/rfc/rfc2119.txt
- [WEBIDL]
- Cameron McCormack. Web IDL. 19 April 2012. W3C Candidate Recommendation. (Work in progress.) URL: https://www.w3.org/TR/2012/CR-WebIDL-20120419/
B.2 Informative references
No informative references.