code: function(id) {
              if (!Crafty.support.audio) return false;
  
              for (var i in this.channels) {
                  if (this.channels[i]._is(id)) return true;
              }
  
              return false;
          }
docs: @
  #Crafty.audio.isPlaying
  @comp Crafty.audio
  @kind Method
  
  @sign public Boolean Crafty.audio.isPlaying(string ID)
  @param {string} id - The id of the audio object
  @return a Boolean indicating whether the audio is playing or not
  
  Check if audio with the given ID is playing or not (on at least one channel).
  
  @example
  ~~~
  var isPlaying = Crafty.audio.isPlaying('music');
  ~~~