text: // 為了避免一直寫document.getElementById
  exports.$ = (id) => {
      return document.getElementById(id);
  }
  
  exports.convertDuration = (time) => {
      const minutes = "0" + Math.floor(time / 60)     // Ex, 單數> '01', 2位數> '010' 
      const seconds = "0" + Math.floor(time - minutes * 60)
      return minutes.substr(-2) + ":" + seconds.substr(-2)
  }
  
  exports.getSupportVideoTypes = () => {
      return ['mp4']
  }
  
  exports.getSupportAudioTypes = () => {
      return ['mp3']
  }
  
  exports.getSupportImageTypes = () => {
      return ['jpg', 'png', 'gif']
  }