我已经成功创建了一个与php的联系表单，提供了各种必需的消息。现在我想添加一个简单的随机算术验证码（非图像）。请参阅下面的匿名（工作）html表单和现有（工作，但没有算术验证码）php。
这个想法是以与其他错误消息相同的方式显示“不正确的答案”，或者传递给Thankyou页面以获得正确填写的表格和正确的答案。我有一个很好的去，但不能让它工作。任何帮助都非常赞赏。
HTML：
<p>Area of interest:
<input type="radio" name="likeit" value="A" checked="checked" /> A
<input type="radio" name="likeit" value="B" /> B
<input type="radio" name="likeit" value="C" /> C</p>
<p>How did you hear about us?
<select name="how">
<option value=""> -- Please select -- </option>
<option>Recommendation</option>
<option>Internet</option>
<option>Advertisement</option>
<option>Other</option>
</select></p>
<p><strong>Your message subject:</strong><br /><input type="text" name="subject" size="35"/></p>
<p><strong>Your message:</strong><br />
<textarea name="comments" rows="10" cols="40"></textarea></p>
<p>Please answer the following arithmetic question: What is <?php echo $digit1;?> + <?php echo $digit2;?>?
<input name="captcha" type="text" size="2" id="captcha"/></p>
<p><input type="submit" value="Send" /></p>
</form>
PHP：
<?php
/* Contact form with arithmetic captcha */
$myemail = "enquiries@X.co.uk";
/* Check all form inputs using check_input function */
$yourname = check_input($_POST['yourname'], "Enter your name");
$email = check_input($_POST['email']);
$telephone = check_input($_POST['telephone']);
$website = check_input($_POST['website']);
$likeit = check_input($_POST['likeit']);
$how_find = check_input($_POST['how']);
$subject = check_input($_POST['subject'], "Add a subject");
$comments = check_input($_POST['comments'], "Add your message");
/* If e-mail is not valid show error message */
if (!preg_match("/([\w\-]+\@[\w\-]+\.[\w\-]+)/", $email))
{
show_error("Email address is not valid");
}
/* If URL is not valid set $website to empty */
if (!preg_match("/^(https?:\/\/+[\w\-]+\.[\w\-]+)/i", $website))
{
$website = '';
}
/* Message for the email */
$message = "Hello!
Your contact form has been submitted by:
Name: $yourname
Email: $email
Telephone: $telephone
URL: $website
Area of interest? $likeit
How did they find us? $how_find
Comments:
$comments
End of message
";
/* Send the message using mail() function */
mail($myemail, $subject, $message);
/* Redirect visitor to the thankyou page */
header('Location: thankyou.html');
exit();
/* Functions used */
function check_input($data, $problem='')
{
$data = trim($data);
$data = stripslashes($data);
$data = htmlspecialchars($data);
if ($problem && strlen($data) == 0)
{
show_error($problem);
}
return $data;
}
function show_error($myError)
{
?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<!--
Head data in here
-->
<html xmlns="http://www.w3.org/1999/xhtml">
<body>
<div id="mainheader">
<div id="mainlogo">
<h1><a href="http://www.X.co.uk/" title="X">
<img style="border:0;width: 260px; height: 160px;" src="images/X.jpg" alt="X" /></a></h1>
</div>
</div>
<div id="content">
<div class="content">
<h2 class="title">Error!</h2>
<p><strong>Please correct the following error:</strong></p>
<p><?php echo $myError; ?></p>
</div>
</div>
<div id="panel">
<div id="main" class="boxed">
<h2 class="heading">Main</h2>
<ul>
<li><a href="index.html">Home</a> </li>
<li><a href="about.html">About</a> </li>
<li><a href="contact.html">Contact</a> </li>
</ul>
</div>
<div id="services" class="boxed">
<h2 class="heading">Services</h2>
<ul>
<li><a href="services.html">Services</a> </li>
<li><a href="recent-projects.html">Recent projects</a> </li>
</ul>
</div>
<div id="pricing" class="boxed">
<h2 class="heading">Pricing</h2>
<ul>
<li><a href="pricing.html">Pricing</a> </li>
</ul>
</div>
<div id="info" class="boxed">
<h2 class="heading">Info</h2>
<ul>
<li><a href="tips-and-tricks.html">Tips and tricks</a> </li>
<li><a href="useful-links.html">Useful links</a> </li>
<li><a href="faq.html">Frequently asked questions</a> </li>
<li><a href="site-map.html">Site map</a> </li>
</ul>
</div>
<div id="contact" class="boxed">
<h2 class="heading">Contact</h2>
<ul>
<li><a href= "mailto:enquiries&#64;X.co.uk">Contact by email</a> </li>
<li><strong>Telephone:<br />X</strong> </li>
</ul>
</div>
</div>
<div id="mainfooter">
<p> &#169; 2011 X<br />Designed by <a href="http://www.X.co.uk/" title="X"><strong>X</strong></a> </p>
<a href="http://validator.w3.org/check?uri=referer" title="Valid XHTML 1.0">
<img style="border:0;width:88px;height:31px" src="images/valid-xhtml10.png" alt="Valid XHTML 1.0" />
</a>
<a href="http://jigsaw.w3.org/css-validator/check/referer" title="Valid CSS!">
<img style="border:0;width:88px;height:31px" src="images/vcss.gif" alt="Valid CSS!" />
</a>
</div>
</body>
</html>
<?php
exit();
}
?>
答案 0 :(得分：12)
通常，验证码的概念是防止自动表单处理。任何非图像比较都很容易解决。
无论如何，我会使用会话来解决这个问题。
只需将预期结果存储在第一页的会话变量中，并确保它匹配第二页
page1.php中：
<?php
session_start();
$digit1 = mt_rand(1,20);
$digit2 = mt_rand(1,20);
if( mt_rand(0,1) === 1 ) {
$math = "$digit1 + $digit2";
$_SESSION['answer'] = $digit1 + $digit2;
} else {
$math = "$digit1 - $digit2";
$_SESSION['answer'] = $digit1 - $digit2;
}
?>
<form method="POST" action="page2.php">
What's <?php echo $math; ?> = <input name="answer" type="text" /><br />
<input type="submit" />
</form>
使page2.php
session_start();
echo "You entered ".htmlentities($_POST['answer'])." which is ";
if ($_SESSION['answer'] == $_POST['answer'] )
echo 'correct';
else
echo 'wrong. We expected '.$_SESSION['answer'];
?>
答案 1 :(得分：0)
使用简单的PHP数学验证码 https://github.com/kmlpandey77/MathCaptcha
一个简单的PHP数学验证码
composer require kmlpandey77/math-captcha
它将返回图像中的Math
创建captcha.php
<?php
require_once 'vendor/autoload.php'; // link to vendor's autoload.php
use Kmlpandey77\MathCaptcha\Captcha;
$captcha = new Captcha();
$captcha->image();
创建form.php
<form action="check.php" method="post">
<p>
Answer it <img src="./captcha.php" alt="" valign="middle"> <input type="text" name="captcha">
</p>
<p><button type="submit" name="submit">Submit</button></p>
</form>
它将以文本形式返回Math
创建form.php
将此代码放在form.php的顶部
<?php
require_once 'vendor/autoload.php'; // link to vendor's autoload.php
use Kmlpandey77\MathCaptcha\Captcha;
?>
并将此代码放入body
<form action="check.php" method="post">
<p>
Answer it <?php echo new Captcha; ?> <input type="text" name="captcha">
</p>
<p><button type="submit" name="submit">Submit</button></p>
</form>
检查用户是否输入了正确的验证码
创建check.php
<?php
require_once 'vendor/autoload.php'; // link to vendor's autoload.php
use Kmlpandey77\MathCaptcha\Captcha;
if(isset($_POST['submit'])){
if(Captcha::check()){
//valid action
echo('<font color="green">Answer is valid</font>');
}else{
echo('<font color="red">Answer is invalid</font>');
}
}