code: function toMS(duration) {
      var i = duration;
  
      // Allow for string durations like 'fast'.
      if ($.fx.speeds[i]) { i = $.fx.speeds[i]; }
  
      return unit(i, 'ms');
    }
docs: ### toMS(duration) Converts given `duration` to a millisecond string.  toMS('fast')   //=> '400ms' toMS(10)       //=> '10ms'