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Steve Agoston (Sony)
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The Gamepad specification defines a low-level interface that represents gamepad devices.

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 and the latest revision of this technical report can be found in the W3C technical reports index at

This is a work in progress.

This document was published by the Web Applications Working Group as a Working Draft. This document is intended to become a W3C Recommendation.

GitHub Issues are preferred for discussion of this specification.

Please see the Working Group's implementation report.

Publication as a Working Draft does not imply endorsement by the W3C Membership. This is a draft document and may be updated, replaced or obsoleted by other documents at any time. It is inappropriate to cite this document as other than work in progress.

This document was produced by a group operating under the W3C Patent Policy. W3C maintains a public list of any patent disclosures made in connection with the deliverables of the group; that page also includes instructions for disclosing a patent. An individual who has actual knowledge of a patent which the individual believes contains Essential Claim(s) must disclose the information in accordance with section 6 of the W3C Patent Policy.

This document is governed by the 1 March 2019 W3C Process Document.

1. Introduction

This section is non-normative.

Some user agents have connected gamepad devices. These devices are desirable and suited to input for gaming applications, and for "10 foot" user interfaces (presentations, media viewers).

Currently, the only way for a gamepad to be used as input would be to emulate mouse or keyboard events, however this would lose information and require additional software outside of the user agent to accomplish emulation.

Meanwhile, native applications are capable of accessing these devices via system APIs.

The Gamepad API provides a solution to this problem by specifying interfaces that allow web applications to directly act on gamepad data.

2. Dependencies

This specification references interfaces from a number of other specifications:

3. Scope

Interfacing with external devices designed to control games has the potential to become large and intractable if approached in full generality. In this specification we explicitly choose to narrow scope to provide a useful subset of functionality that can be widely implemented and broadly useful.

Specifically, we choose to only support the functionality required to support gamepads. Support for gamepads requires two input types: buttons and axes. Both buttons and axes are reported as analog values, buttons ranging from [0..1], and axes ranging from [-1..1].

While the primary goal is support for gamepad devices, supporting these two types of analog inputs allows support for other similar devices common to current gaming systems including joysticks, driving wheels, pedals, and accelerometers. As such, the name "gamepad" is exemplary rather than trying to be a generic name for the entire set of devices addressed by this specification.

We specifically exclude support for more complex devices that may also be used in some gaming contexts, including those that that do motion sensing, depth sensing, video analysis, gesture recognition, and so on.

4. Gamepad interface

This interface defines an individual gamepad device.

interface Gamepad {
  readonly attribute DOMString id;
  readonly attribute long index;
  readonly attribute boolean connected;
  readonly attribute DOMHighResTimeStamp timestamp;
  readonly attribute GamepadMappingType mapping;
  readonly attribute FrozenArray<double> axes;
  readonly attribute FrozenArray<GamepadButton> buttons;
id attribute
An identification string for the gamepad. This string identifies the brand or style of connected gamepad device. Typically, this will include the USB vendor and a product ID.
index attribute
The index of the gamepad in the Navigator. When multiple gamepads are connected to a user agent, indices MUST be assigned on a first-come, first-serve basis, starting at zero. If a gamepad is disconnected, previously assigned indices MUST NOT be reassigned to gamepads that continue to be connected. However, if a gamepad is disconnected, and subsequently the same or a different gamepad is then connected, the lowest previously used index MUST be reused.
connected attribute
Indicates whether the physical device represented by this object is still connected to the system. When a gamepad becomes unavailable, whether by being physically disconnected, powered off or otherwise unusable, the connected attribute MUST be set to false.
timestamp attribute
Last time the data for this gamepad was updated. Timestamp is a monotonically increasing value that allows the author to determine if the axes and button data have been updated from the hardware. The value must be relative to the navigationStart attribute of the PerformanceTiming interface. Since values are monotonically increasing they can be compared to determine the ordering of updates, as newer values will always be greater than or equal to older values. If no data has been received from the hardware, the value of the timestamp attribute should be the time relative to navigationStart when the Gamepad object was first made available to script.
mapping attribute
The mapping in use for this device. If the user agent has knowledge of the layout of the device, then it SHOULD indicate that a mapping is in use by setting this property to a known mapping name. Currently the only known mapping is "standard", which corresponds to the Standard Gamepad layout. If the user agent does not have knowledge of the device layout and is simply providing the controls as represented by the driver in use, then it MUST set the mapping property to the empty string.
axes attribute
Array of values for all axes of the gamepad. All axis values MUST be linearly normalized to the range [-1.0 .. 1.0]. If the controller is perpendicular to the ground with the directional stick pointing up, -1.0 SHOULD correspond to "forward" or "left", and 1.0 SHOULD correspond to "backward" or "right". Axes that are drawn from a 2D input device SHOULD appear next to each other in the axes array, X then Y. It is RECOMMENDED that axes appear in decreasing order of importance, such that element 0 and 1 typically represent the X and Y axis of a directional stick. The same object MUST be returned until the user agent needs to return different values (or values in a different order).
buttons attribute
Array of button states for all buttons of the gamepad. It is RECOMMENDED that buttons appear in decreasing importance such that the primary button, secondary button, tertiary button, and so on appear as elements 0, 1, 2, ... in the buttons array. The same object MUST be returned until the user agent needs to return different values (or values in a different order).

5. GamepadButton Interface

This interface defines the state of an individual button on a gamepad device.

interface GamepadButton {
  readonly attribute boolean pressed;
  readonly attribute boolean touched;
  readonly attribute double value;
pressed attribute
The pressed state of the button. This property MUST be true if the button is currently pressed, and false if it is not pressed. For buttons which do not have a digital switch to indicate a pure pressed or released state, the user agent MUST choose a threshold value to indicate the button as pressed when its value is above a certain amount. If the platform API gives a recommended value, the user agent SHOULD use that. In other cases, the user agent SHOULD choose some other reasonable value.
touched attribute
The touched state of the button. If the button is capable of detecting touch this property MUST be true if the button is currently being touched and false otherwise. If the button is not capable of detecting touch and is capable of reporting an analog value this property MUST be true if the value property is greater than zero and false if the value is 0. If the button is not capable of detecting touch and can only report a digital value this property MUST mirror the pressed value.
value attribute
For buttons that have an analog sensor, this property MUST represent the amount which the button has been pressed. All button values MUST be linearly normalized to the range [0.0 .. 1.0]. 0.0 MUST mean fully unpressed, and 1.0 MUST mean fully pressed. For buttons without an analog sensor, only the values 0.0 and 1.0 for fully unpressed and fully pressed MUST be provided.

6. GamepadMappingType enum

This enum defines the set of known mappings for a Gamepad.

enum GamepadMappingType {
The empty string indicates that no mapping is in use for this gamepad.
The Gamepad's controls have been mapped to the Standard Gamepad layout.

8. GamepadEvent Interface


interface GamepadEvent: Event {
  constructor(DOMString type, GamepadEventInit eventInitDict);
  [SameObject] readonly attribute Gamepad gamepad;
The single gamepad attribute provides access to the associated gamepad data for this event.

8.1 GamepadEventInit dictionary

dictionary GamepadEventInit : EventInit {
  required Gamepad gamepad;
gamepad member
The gamepad associated with this event.

9. Remapping

Each device manufacturer creates many different products and each has unique styles and layouts of buttons and axes. It is intended that the user agent support as many of these as possible.

Additionally there are de facto standard layouts that have been made popular by game consoles. When the user agent recognizes the attached device, it is RECOMMENDED that it be remapped to a canonical ordering when possible. Devices that are not recognized should still be exposed in their raw form.

There is currently one canonical device, the "Standard Gamepad". The standard gamepad has 4 axes, and up to 17 buttons. When remapping, the indices in axes[] and buttons[] should correspond as closely as possible to the physical locations in the diagram below. Additionally, the mapping property of the Gamepad SHOULD be set to the string "standard".

The "Standard Gamepad" physical button locations are layed out in a left cluster of four buttons, a right cluster of four buttons, a center cluster of three buttons, and a pair of front facing buttons on the left and right side of the gamepad. The four axes of the "Standard Gamepad" are associated with a pair of analog sticks, one on the left and one on the right. The following table describes the buttons/axes and their physical locations.

Button/Axis Location
buttons[0] Bottom button in right cluster
buttons[1] Right button in right cluster
buttons[2] Left button in right cluster
buttons[3] Top button in right cluster
buttons[4] Top left front button
buttons[5] Top right front button
buttons[6] Bottom left front button
buttons[7] Bottom right front button
buttons[8] Left button in center cluster
buttons[9] Right button in center cluster
buttons[10] Left stick pressed button
buttons[11] Right stick pressed button
buttons[12] Top button in left cluster
buttons[13] Bottom button in left cluster
buttons[14] Left button in left cluster
buttons[15] Right button in left cluster
axes[0] Horizontal axis for left stick (negative left/positive right)
axes[1] Vertical axis for left stick (negative up/positive down)
axes[2] Horizontal axis for right stick (negative left/positive right)
axes[3] Vertical axis for right stick (negative up/positive down)
Figure 1 Visual representation of a standard gamepad layout.

10. Usage Examples

This section is non-normative.

The example below demonstrates typical access to gamepads. Note the relationship with the requestAnimationFrame() method.

function runAnimation() {
    for (const pad of navigator.getGamepads()) {
      // todo; simple demo of displaying pad.axes and pad.buttons

Best Practice 1: Coordination with requestAnimationFrame()

Interactive applications will typically be using the requestAnimationFrame() method to drive animation, and will want coordinate animation with user gamepad input. As such, the gamepad data should be polled as closely as possible to immediately before the animation callbacks are executed, and with frequency matching that of the animation. That is, if the animation callbacks are running at 60Hz, the gamepad inputs should also be sampled at that rate.

11. The gamepadconnected event

User agents implementing this specification must provide a new DOM event, named gamepadconnected. The corresponding event MUST be of type GamepadEvent and MUST fire on the window object. Registration for and firing of the gamepadconnected event MUST follow the usual behavior of DOM Events. [DOM]

A user agent MUST dispatch this event type to indicate the user has connected a gamepad. If a gamepad was already connected when the page was loaded, the gamepadconnected event SHOULD be dispatched when the user presses a button or moves an axis.

12. The gamepaddisconnected event

User agents implementing this specification must provide a new DOM event, named gamepaddisconnected. The corresponding event MUST be of type GamepadEvent and MUST fire on the window object. Registration for and firing of the gamepaddisconnected event MUST follow the usual behavior of DOM Events. [DOM]

When a gamepad is disconnected from the user agent, if the user agent has previously dispatched a gamepadconnected event for that gamepad to a window, a gamepaddisconnected event MUST be dispatched to that same window.

13. Other events

More discussion needed, on whether to include or exclude axis and button changed events, and whether to roll them more together (gamepadchanged?), separate somewhat (gamepadaxischanged?), or separate by individual axis and button.

14. 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, RECOMMENDED, and SHOULD in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.

This specification defines conformance criteria that apply to a single product: the user agent that implements the interfaces that it contains.

A. Acknowledgements

This section is non-normative.

Many have made contributions in code, comments, or documentation:

Please let me know if I have inadvertently omitted your name.

B. References

B.1 Normative references

DOM Standard. Anne van Kesteren. WHATWG. Living Standard. URL:
High Resolution Time. Jatinder Mann. W3C. 17 December 2012. W3C Recommendation. URL:
HTML Standard. Anne van Kesteren; Domenic Denicola; Ian Hickson; Philip Jägenstedt; Simon Pieters. WHATWG. Living Standard. URL:
Navigation Timing. Zhiheng Wang. W3C. 17 December 2012. W3C Recommendation. URL:
Key words for use in RFCs to Indicate Requirement Levels. S. Bradner. IETF. March 1997. Best Current Practice. URL:
Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words. B. Leiba. IETF. May 2017. Best Current Practice. URL:
Web IDL. Boris Zbarsky. W3C. 15 December 2016. W3C Editor's Draft. URL: