微信页面监听摇一摇事件，并伴有音效

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微信页面监听摇一摇事件，并伴有音效

最近要写一个微信网页，需要监听手机摇动事件，并且伴随有声音

在HTML5，devicemotion事件deviceorientation特性的运动传感器的封装时间装置，你可以通过改变运动时间获取设备的状态，加速和其他数据（有另一个角度deviceorientation事件提供设备，定位等信息）。

而通过DeviceMotion对设备运动状态的判断，则可以帮助我们在网页上就实现“摇一摇”的交互效果。

把监听事件绑定给 deviceMotionHandler

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if (window.DeviceMotionEvent) {
    window.addEventListener('devicemotion', deviceMotionHandler, false);
} else {
    alert('本设备不支持devicemotion事件');
}
获取设备加速度信息 accelerationIncludingGravity

function deviceMotionHandler(eventData) {
    var acceleration = eventData.accelerationIncludingGravity,
    x, y, z;
    x = acceleration.x;
    y = acceleration.y;
    z = acceleration.z;
    document.getElementById("status").innerHTML = "x:"+x+"<br />y:"+y+"<br />z:"+z;
}

“摇一摇”的动作既“一定时间内设备了一定距离”，因此通过监听上一步获取到的x, y, z 值在一定时间范围内 的变化率，即可进行设备是否有进行晃动的判断。而为了防止正常移动的误判，需要给该变化率设置一个合适的临界 值。

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var SHAKE_THRESHOLD = 800;
var last_update = 0;
var x = y = z = last_x = last_y = last_z = 0;

if (window.DeviceMotionEvent) {
    window.addEventListener('devicemotion', deviceMotionHandler, false);
} else {
alert('本设备不支持devicemotion事件');
}

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;
    }
}

100毫秒进行一次位置判断，若前后x, y, z间的差值的绝对值和时间比率超过了预设的阈值，则判断设备进行 了摇晃操作。

下面是我改写的代码

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<audio style="display: none;" src="http://xunlei.sc.chinaz.com/files/download/sound1/201410/5018.mp3" id="musicBox" preload="preload"  controls></audio>
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<script>
    var SHAKE_THRESHOLD = 3000;    
    var last_update = 0;    
    var x=y=z=last_x=last_y=last_z=0;   
var  media;
media= document.getElementById("musicBox");
function init(){
   	last_update=new Date().getTime();
    	if (window.DeviceMotionEvent) {
    		window.addEventListener('devicemotion',deviceMotionHandler, false);  
    	} else{
alert('not support mobile event');
}
}
    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; 	
    		if (speed > SHAKE_THRESHOLD) {    
    			media.play();
    		}    
    		last_x = x;    
    		last_y = y;    
    		last_z = z;    
    	}
    }
    window.onload = function(){
    	init();
    }
</script>