if (window.DeviceMotionEvent) {
window.addEventListener('devicemotion', deviceMotionHandler, false);
} else {
alert('你的手机太差了，买个新的吧。');
}

function deviceMotionHandler(eventData) {
var acceleration = eventData.accelerationIncludingGravity;
var curTime = new Date().getTime();
if ((curTime - last_update) > 100) {
var diffTime = curTime - last_update;
last_update = curTime;
x = acceleration.x;
y = acceleration.y;
z = acceleration.z;
var speed = Math.abs(x + y + z - last_x - last_y - last_z) / diffTime * 10000;
var status = document.getElementById("status");
if (speed > SHAKE_THRESHOLD) {
doResult();
}
last_x = x;
last_y = y;
last_z = z;
}
}