Want to allow people to register on your site, but don’t want to be flooded with spam users? Try this:
add_action( 'register_form', 'add_register_field' );
function add_register_field() { ?>
<p>
<label><?php _e('What is the name of the ship in the TV show Firefly?') ?><br />
<input type="text" name="user_proof" id="user_proof" class="input" size="25" tabindex="20" /></label>
</p>
<?php }
add_action( 'register_post', 'add_register_field_validate', 10, 3 );
function add_register_field_validate( $sanitized_user_login, $user_email, $errors) {
if (!isset($_POST[ 'user_proof' ]) || empty($_POST[ 'user_proof' ])) {
return $errors->add( 'proofempty', '<strong>ERROR</strong>: You did not answer the proof-of-humanship question.' );
} elseif ( strtolower( $_POST[ 'user_proof' ] ) != 'serenity' ) {
return $errors->add( 'prooffail', '<strong>ERROR</strong>: You did not answer the proof-of-humanship question correctly.' );
}
}
This adds an extra box to the register screen with the question “What is the name of the ship in the TV show Firefly?” The user-provided answer is then compared to the official answer. If correct, the user is registered, otherwise WordPress-friendly error(s) are returned.
