Type: String
The mask property of the FileFolder class contains the masking string that is used to access the files in the FileFolder object returned from the files method. The default value is "*.*".
To specify multiple masks, separate them using the vertical bar (|) character; for example, "*.txt | *.log | *.cat".
Specifying "*.*" as a mask value results in all files and subfolders in the folder being returned by the FileFolder class files method.