code: function SpriteSheetLoader(loadItem, preferXHR) {
  		this.AbstractLoader_constructor(loadItem, preferXHR, createjs.AbstractLoader.SPRITESHEET);
  
  		// protected properties
  		/**
  		 * An internal queue which loads the SpriteSheet's images.
  		 * @method _manifestQueue
  		 * @type {LoadQueue}
  		 * @private
  		 */
  		this._manifestQueue = null;
  	}
docs: constructor 
  A loader for EaselJS SpriteSheets. Images inside the spritesheet definition are loaded before the loader
  completes. To load SpriteSheets using JSONP, specify a {{#crossLink "LoadItem/callback:property"}}{{/crossLink}}
  as part of the {{#crossLink "LoadItem"}}{{/crossLink}}. Note that the {{#crossLink "JSONLoader"}}{{/crossLink}}
  and {{#crossLink "JSONPLoader"}}{{/crossLink}} are higher priority loaders, so SpriteSheets <strong>must</strong>
  set the {{#crossLink "LoadItem"}}{{/crossLink}} {{#crossLink "LoadItem/type:property"}}{{/crossLink}} property
  to {{#crossLink "AbstractLoader/SPRITESHEET:property"}}{{/crossLink}}.
  
  The {{#crossLink "LoadItem"}}{{/crossLink}} {{#crossLink "LoadItem/crossOrigin:property"}}{{/crossLink}} as well
  as the {{#crossLink "LoadQueue's"}}{{/crossLink}} `basePath` argument and {{#crossLink "LoadQueue/_preferXHR"}}{{/crossLink}}
  property supplied to the {{#crossLink "LoadQueue"}}{{/crossLink}} are passed on to the sub-manifest that loads
  the SpriteSheet images.
  
  Note that the SpriteSheet JSON does not respect the {{#crossLink "LoadQueue/_preferXHR:property"}}{{/crossLink}}
  property, which should instead be determined by the presence of a {{#crossLink "LoadItem/callback:property"}}{{/crossLink}}
  property on the SpriteSheet load item. This is because the JSON loaded will have a different format depending on
  if it is loaded as JSON, so just changing `preferXHR` is not enough to change how it is loaded.
  @class SpriteSheetLoader
  @param {LoadItem|Object} loadItem
  @extends AbstractLoader
  @constructor