var vibrateInterval;
    // Starts vibration at passed in level
    function startVibrate(duration) {
        navigator.vibrate(duration);
    }
    // Stops vibration
    function stopVibrate() {
        // Clear interval and stop persistent vibrating
        if (vibrateInterval) clearInterval(vibrateInterval);
        navigator.vibrate(0);
    }
    // Start persistent vibration at given duration and interval
    // Assumes a number value is given
    function startPeristentVibrate(duration, interval) {
        vibrateInterval = setInterval(function() {
            startVibrate(duration);
        }, interval);
    }
    //IOS无效