//WordPress新用户注册随机数学验证码
function add_security_question_fields() {
//获取两个随机数, 范围0~9
$num1=rand(1,9);
$num2=rand(2,9);
//最终网页中的具体内容
echo \"<p><label for=\'math\' class=\'small\'>验证码：$num1 + $num2 = ? </label><input type=\'text\' name=\'sum\' class=\'input\' value=\'\' size=\'25\'>\"
.\"<input type=\'hidden\' name=\'num1\' value=\'$num1\'>\"
.\"<input type=\'hidden\' name=\'num2\' value=\'$num2\'></p>\";}
add_action(\'register_form\',\'add_security_question_fields\');
add_action( \'register_post\', \'add_security_question_validate\', 10, 3 );
function add_security_question_validate( $sanitized_user_login, $user_email, $errors) {
$sum=$_POST[\'sum\'];//用户提交的计算结果
switch($sum){
//得到正确的计算结果则直接跳出
case $_POST[\'num1\']+$_POST[\'num2\']:break;
//未填写结果时的错误讯息
case null:wp_die(\'错误：请输入验证码！\');break;
//计算错误时的错误讯息
default:wp_die(\'错误：验证码错误,请重试！\');}}
add_action( \'add_security_question\',\'register_form\' );