(PHP 4 >= 4.0.2, PHP 5 < 5.3.0, PECL fdf SVN)
fdf_set_javascript_action — Sets an javascript action of a field
$fdf_document
   , string $fieldname
   , int $trigger
   , string $script
   ) : boolSets a javascript action for the given field.
fdf_documentThe FDF document handle, returned by fdf_create(), fdf_open() or fdf_open_string().
fieldnameName of the FDF field, as a string.
trigger
script
   成功时返回 TRUE, 或者在失败时返回 FALSE。