监听Audio的播放状态

监听音乐播放状态：改变播放或暂停按钮
    watchMusicState(){
        let _this = this;
        let $audio = document.getElementsByTagName('audio')[0];//获取音乐DOM节点
        let playOrPause = document.getElementsByClassName('playOrPause')[0];
        // console.log($audio);
        $audio.addEventListener("playing", function(){        //播放状态Doing
                playOrPause.src = require('../assets/img/pause.svg')//背景音乐是播放还是暂停
                _this.playState = true;//播放状态
        });$audio.addEventListener("pause", function(){ //暂停状态Doing
                playOrPause.src = require('../assets/img/play.svg')//背景音乐是播放还是暂停
                _this.playState = false;//暂停状态

        });
    },