Adds a new DateFormField.

<void> FormFieldCollection.addDateFormField(<Number> emptyWidth, [<RequestDateFormFieldCallback> callback], [<ErrorCallback> errorCallback])


Parameter Description
emptyWidth Specifies the horizontal extension, in twips, of the DateFormField, when there is no date set. When this parameter is set to 0, a default value is used.
callback Optional. Receives the added DateFormField.
errorCallback Optional. Is called when the operation failed with an error.