GamepadButton

The GamepadButton interface defines an individual button of a gamepad or other controller, allowing access to the current state of different types of buttons available on the control device.

A GamepadButton object is returned by querying any value of the array returned by the buttons property of the Gamepad interface.

Properties

GamepadButton.value Read only

A double value used to represent the current state of analog buttons, such as the triggers on many modern gamepads. The values are normalized to the range 0.0 —1.0, with 0.0 representing a button that is not pressed, and 1.0 representing a button that is fully pressed.

GamepadButton.pressed Read only

A boolean value indicating whether the button is currently pressed (true) or unpressed (false).

Example

The following code is taken from my Gamepad API button demo (you can view the demo live, and find the source code on Github.) Note the code fork — in Chrome Navigator.getGamepads needs a webkit prefix and the button values are stored as an array of double values, whereas in Firefox Navigator.getGamepads doesn't need a prefix, and the button values are stored as an array of GamepadButton objects; it is the GamepadButton.value or GamepadButton.pressed properties of these we need to access, depending on what type of buttons they are. In this simple example I've just allowed either.

function gameLoop() {
  if(navigator.webkitGetGamepads) {
    var gp = navigator.webkitGetGamepads()[0];
    if(gp.buttons[0] == 1) {
      b--;
    } else if(gp.buttons[1] == 1) {
      a++;
    } else if(gp.buttons[2] == 1) {
      b++;
    } else if(gp.buttons[3] == 1) {
      a--;
    }
  } else {
    var gp = navigator.getGamepads()[0];
    if(gp.buttons[0].value > 0 || gp.buttons[0].pressed == true) {
      b--;
    } else if(gp.buttons[1].value > 0 || gp.buttons[1].pressed == true) {
      a++;
    } else if(gp.buttons[2].value > 0 || gp.buttons[2].pressed == true) {
      b++;
    } else if(gp.buttons[3].value > 0 || gp.buttons[3].pressed == true) {
      a--;
    }
  }
  ball.style.left = a*2 + "px";
  ball.style.top = b*2 + "px";
  var start = rAF(gameLoop);
};

Specifications

Browser compatibility

1. From version 24 until version 28 (exclusive): this feature is behind the dom.gamepad.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.

See also

Using the Gamepad API