/**
 * WordPress 注册表单添加验证问题(支持多个随机问题)
 * http://www.wpdaxue.com/add-a-security-question-to-the-register-screen.html
 */
function rand_reg_question(){
	$register_number=rand(0,1); // 设置随机数的返回范围
	$_SESSION['register_number']=$register_number;
}
add_action('login_head','rand_reg_question');
 
global $register_questions;
global $register_answers;
// 添加问题数组
$register_questions=array('中国的首都在哪里？','Google是哪个国家的公司？');
// 添加答案数组（与上面的问题对应）
$register_answers=array('北京','美国');
 
add_action( 'register_form', 'add_security_question' );
function add_security_question() {
	global $register_questions;
	$register_number=$_SESSION['register_number'];
	?>
	<p>
		<label><?php echo $register_questions[$register_number];?><br />
			<input type="text" name="user_proof" id="user_proof" class="input" size="25" tabindex="20" />
		</label>
	</p>
<?php }
 
add_action( 'register_post', 'add_security_question_validate', 10, 3 );
function add_security_question_validate( $sanitized_user_login, $user_email, $errors) {
	global $register_answers;
	$register_number=$_SESSION['register_number'];
	if (!isset($_POST[ 'user_proof' ]) || empty($_POST[ 'user_proof' ])) {
		return $errors->add( 'proofempty', '<strong>错误</strong>: 您还没有回答问题。' );
	} elseif ( strtolower( $_POST[ 'user_proof' ] ) != $register_answers[$register_number] ) {
		return $errors->add( 'prooffail', '<strong>错误</strong>: 您的回答不正确。' );
	}
}