code: function(container) {
              if( typeof container === STRING) {
                  var id = container;
                  container = Kinetic.document.getElementById(container);
                  if (!container) {
                      throw 'Can not find container in document with id ' + id;
                  }
              }
              this._setAttr(CONTAINER, container);
              return this;
          }
docs: set container dom element which contains the stage wrapper div element
  @method
  @memberof Kinetic.Stage.prototype
  @param {DomElement} container can pass in a dom element or id string