H5监听页面隐藏与展示

mounted() {  
  document.addEventListener('visibilitychange', this.handleVisiable)  
},  
destroyed() {  
  document.removeEventListener('visibilitychange', this.handleVisiable)  
},  
methods: {  
  handleVisiable(e) {  
    if (e.target.visibilityState === 'visible') { // 页面显示
      // TODO...
    }  else if (e.target.visibilityState === 'hidden') { // 页面隐藏
        // TODO...
    }
}