navigator.webkitGamepads
GamepadList
  0: undefined
  1: undefined
  2: undefined
  3: undefined
  length: 4
  __proto__: GamepadList

function updateStatus() {
    window.webkitRequestAnimationFrame(updateStatus);

    var gamepads = navigator.webkitGamepads;

    var data = '';
    for (var padindex = 0; padindex < gamepads.length; ++padindex)
    {
        var pad = gamepads[padindex];
        if (!pad) continue;
        data += '<pre>' + pad.index + ": " + pad.id + "<br/>";
        for (var i = 0; i < pad.buttons.length; ++i)
            data += "button" + i + ": " + pad.buttons[i] + "<br/>";
        for (var i = 0; i < pad.axes.length; ++i)
            data += "axis" + i + ": " + pad.axes[i] + "<br/>";
    }
    document.body.innerHTML = data;
}

window.webkitRequestAnimationFrame(updateStatus);

var ua = navigator.userAgent;
if (ua.toLowerCase().indexOf("chrome") != -1)
    gp = navigator.getGamePads();

var gLen = this.gamePads.length;
done = false;
idx = 0;

while (!done)
{
    if (this.gamePads[idx] !== null)
    {
        if (gid == this.gamePads[idx].index)
        {
        //Here, choose this GamePad as the selected GamePad, based upon the index number as per the W3C recommendation ...

            selectedGamePadIndex = gid;
            selectedGamePad = this.gamePads[idx];
            done = true;

        //End if
        }

    //End if
    }

    //Update counter in case we haven't selected one of the available GamePads above ...

    idx++;

    if (idx >= gLen)
        done = true;    //Exit loop altogether if we've exhausted the list of available GamePads

//End while
}