基于HTML5实现类似微信手机摇一摇功能(计算摇动次数)

var jsonObject=null;
        // 当页面加载完以后会执行window.onload
        window.onload = function() {
            var times = -1; // 记录摇动次数
            var last_time = 0;
            var borderSpeed = 800;  // 加速度变化临界值
            var x = y = z = last_x = last_y = last_z = 0;
            if (window.DeviceMotionEvent) {
                window.addEventListener('devicemotion',shake,false);
            }
            else
            {
                alert('您的设备不支持摇一摇哦');
            }
            // 每次手机移动的时候都会执行下面shake函数的代码
            function shake(eventData)
            {
                var acceleration = eventData.accelerationIncludingGravity;
                var curTime = new Date().getTime();
                var diffTime  = curTime-last_time;
                // 每隔100ms进行判断
                if (diffTime>100) {
                    x = acceleration.x;
                    y = acceleration.y;
                    z = acceleration.z;
                    var speed = Math.abs(x + y + z - last_x - last_y - last_z) / diffTime * 10000;
                    // 判断手机确实发生了摇动而不是正常的移动
                    if (speed>borderSpeed) {
                        times++;
                        document.getElementById("text").innerHTML=times+" times";
                        // 用户的微信昵称和头像连接发送一次即可，不需要每次都发送
                        if (times==0)
                        {
                            document.forms["insertForm"].headimg.value =img ;
                            document.forms["insertForm"].user.value = nickname;
                        }
                        document.forms["insertForm"].time.value = times;
                    }
                    last_time = curTime;
                    last_x = x;
                    last_y = y;
                    last_z = z;
                }
            }
        }

<img src="hand.png">
<br/><font size="16" color="red" id="text"></font>