Web Gamepad APIがDirectInputでとりあえず動いたコード

gamepad.html

<div id="GamePadUI">
buttons<input id="b" type="text"><br/>
axis0<input id="a0" type="range"><br/>
axis1<input id="a1" type="range"><br/>
axis2<input id="a2" type="range"><br/>
axis3<input id="a3" type="range"><br/>
</div>
<script>
UI={};UI.a=[];
UI.b=document.getElementById("b");
UI.a[0]=document.getElementById("a0");UI.a[1]=document.getElementById("a1");
UI.a[2]=document.getElementById("a2");UI.a[3]=document.getElementById("a3");
UI.update=function(buttons, axes){
	var str="";
	for(i=0; i<buttons.length; i++)str+=(buttons[i].pressed)?1:0;
	UI.b.value=str;
	for(i=0; i<axes.length; i++)UI.a[i].value=axes[i]*50+50;
}
var gamepads=[];
conn=function(e){
	var gp=e.gamepad, str="";
	if(e.type=="gamepadconnected"){
		str=`接続#${gp.index}, ${gp.id}`;
		str+=`${gp.buttons.length}ボタン, ${gp.axes.length}軸.`;
		gamepads[gp.index]=gp;
	}else{
		str=`切断#${gp.index}, ${gp.id}.`;
		delete gamepads[gp.index];
	}
}
update=function(now){
	var gp;
	if(navigator.webkitGetGamepads){
		gp=navigator.webkitGetGamepads()[0];
	}else{
		gp=navigator.getGamepads()[0];
	}
	if(gp==null){setTimeout(arguments.callee,1000);return;}
	UI.update(gp.buttons, gp.axes);
	setTimeout(arguments.callee,1000/60);
}
window.addEventListener("gamepadconnected", conn);
window.addEventListener("gamepaddisconnected", conn);
update();
</script>