The FILE_EXTENSION function takes a single parameter, normally an external data property, and returns the file extension referenced by that property as a string. This function is intended for use with external data properties as a part of the attached document’s functionality. If the external data property provided as a parameter does not currently reference a file, the function will return an empty string. The return value from this function is undefined when the parameter provided is not an external data property.
- File Name Required string parameter; specifies the file whose file extension is to be returned. While the data type of this parameter is a string, the intended parameter is a property of data type external data. The file extension of the file referenced by such a property is returned by this function. If the property does not reference a file, the function returns an empty string.
Supported Return Types