(PHP 4, PHP 5)
fdf_set_ap — Set the appearance of a field
Sets the appearance of a field (i.e. the value of the /AP key).
The FDF document handle, returned by fdf_create(), fdf_open() or fdf_open_string().
The possible values FDFNormalAP, FDFRolloverAP and FDFDownAP.
成功时返回 TRUE, 或者在失败时返回 FALSE.