SOURCE

var Player = {
  template: '#player-template',
  methods: {
    play: function () {
      alert('play')
    }
  }
}
new Yox({
  el: '#app',
  template: '#template',
  methods: {
    play: function () {
      this.$refs.player.play()
    }
  },
  components: {
    Player: Player
  }
})

<div id="app"></div>
<script id="player-template" type="text/plain">
	<div class="player">
  	Player
  </div>
</script>
<script id="template" type="text/plain">
	<div>
  	<button on-click="play()">
    	Play
    </button>
    <Player ref="player" />
  </div>
</script>