(PHP 4 >= 4.0.2, PHP 5)
fdf_set_opt — Sets an option of a field
Sets options of the given field.
The FDF document handle, returned by fdf_create(), fdf_open() or fdf_open_string().
Name of the FDF field, as a string.
成功时返回 TRUE, 或者在失败时返回 FALSE.