Name of the FDF field, as a string.
This parameter will be stored as a string unless it is an array. In this case all array elements will be stored as a value array.
In older versions of the FDF toolkit last parameter determined if the field value was to be converted to a PDF Name (= 1) or set to a PDF String (= 0).
The value is no longer used in the current toolkit version 5.0. For compatibility reasons it is still supported as an optional parameter beginning with PHP 4.3, but ignored internally.