有些方法可以防止机器人垃圾邮件与/或验证码：

<form method="post" action="send.PHP">
              <ol>
                <li>
                  <label for="name">Name</label>
                  <input type="text" name="name" value="">
                </li>
                <li>
                  <label for="email">Email</label>
                  <input type="text" name="email">
                </li>
                <!-- We hide this with CSS,that's why it has an ID. -->
                <li id="user">
                  <label for="username">Username</label>
                  <input type="text" name="username">
                </li>
                <!-- //end -->
                <li>
                  <input type="submit" name="submit" value="Send It!">
                </li>
              </ol>
            </form>

您可以看到用户名字段将被隐藏.机器人无法识别这个.
您之后需要做的只是验证该字段在您的后端代码是空的.

<?PHP

            if( !isset($_POST['name'])) { die("No Direct Access"); }  // Make sure the form has actually been submitted

            $name = $_POST['name'];
            $email = $_POST['email'];
            $spam = $_POST['username']; // Bot trap

            if($spam) {  // If the hidden field is not empty,it's a bot
                die("No spamming allowed bitch!"); 
            } else {
                // Process the form like normal
            }

使用模块BOTCHA Spam Prevention可以更容易地完成上述过程

此外,您可以看看这些文章,以获得更好的整体观点.

Green-beast和web design,但是您也可以在网络上找到像这样的几十个文章