title: How to add attributes with custom videojs Button
body: <p>I am struggling adding data-attributes to a custom button I have created for an audio js player. It will be a bootstrap collapsible trigger to text files. I think I must use the createEl() function however I can not get it to work with my implementation.</p>
  
  <p>I am trying to add attributes for:</p>
  
  <pre><code>'data-toggle': 'collapse',
  'data-target': '#' + audioID,
  'aria-expanded': 'false'**strong text**
  </code></pre>
  
  <p>thanks for any help you have.</p>
  
  <pre><code>let audioBtnComponent = videojs.getComponent('Button')
  
  let audioTextBtn = videojs.extend(audioBtnComponent, {
      constructor: function () {
          audioBtnComponent.apply(this, arguments)
          this.controlText('Toggle text for audio player')
          // this.createEl({}, {}, { 'class': 'Fudge' })
     },
     handleClick: function () {
      accordionElem[i].classList.toggle('audio-text-open')
      audioList[i].closest('.video-js').classList.toggle('audio-text-open')
     },
     buildCSSClass: function () {
         return 'accordion-trigger audio-text-accordion-trigger collapsed'
     },
     //createEl: function (type, properties, attributes) {
       //  return('button', {}, {'data-toggle': 'collapes'})
      //}
  })
  
  videojs.registerComponent('audioTextBtn', audioTextBtn)
  
  let audioPlayer = videojs(audioList[i])
  audioPlayer.getChild('controlBar').addChild('audioTextBtn', {})
  </code></pre>