code: function() {
              for (var i = 0; i < this.channels.length; i++) {
                  var chan = this.channels[i];
                  /*
                     * Second test looks for stuff that's out of use,
                     * but fallen foul of Chromium bug 280417
                     */
                  if (
                      chan.active === false ||
                      (chan.obj.ended &&
                          chan.repeat <= this.sounds[chan.id].played)
                  ) {
                      chan.active = true;
                      return chan;
                  }
              }
              // If necessary, create a new element, unless we've already reached the max limit
              if (i < this.maxChannels) {
                  var c = {
                      obj: this.audioElement(),
                      active: true,
                      // Checks that the channel is being used to play sound id
                      _is: function(id) {
                          return this.id === id && this.active;
                      }
                  };
                  this.channels.push(c);
                  return c;
              }
              // In that case, return null
              return null;
          }
docs: Finds an unused audio element, marks it as in use, and return it.