/* set content type for Adobe FDF */
fdf_header();
/* start new fdf */
$fdf = fdf_create();
/* set field "foo" to value "bar" */
$fdf_set_value($fdf, "foo", "bar");
/* tell client to display FDF data using "fdf_form.pdf" */
fdf_set_file($fdf, "http://www.example.com/fdf_form.pdf");
/* output fdf */
fdf_save();
/* clean up */
fdf_close();
?>