php中联系人表单功能的问题

在您阅读代码之前，我已经尝试将每个部分划分为各自的php文件，并仅使用requires获取代码，但是使用requires或将所有代码放在同一个文件中，我似乎都会遇到相同的错误。我认为这可能和我使用的PHP版本有关

我似乎在后端部分第3行的提交时出错。属于未定义的属性

第二个错误是用户反馈部分中未定义的错误

我以前使用过此模板，并已成功使用

我正在Windows 8.1 Pro PC上使用WAMP运行PHP5.4.12和Apache 2.4.4

任何帮助都将不胜感激

/** BACKEND **/

<?php
if($_POST['submit'])
{
    $fName=$_POST['fName'];
    $topic=$_POST['topic'];
    $email=$_POST['email'];
    $message=$_POST['message'];

    function verify_email($email)
        {
             if(!preg_match('/^[_A-z0-9-]+((\.|\+)[_A-z0-9-]+)*@[A-z0-9-]+(\.[A-z0-9-]+)*(\.[A-z]{2,4})$/',$email))
             {
            return false;
             }
             else
             {
                 return $email;
             }
    }

    function verify_email_dns($email)
        {
            list($name, $domain) = split('@',$email);

            if(!checkdnsrr($domain,'MX'))
            {
                return false;
            }

            else
            {
                return $email;
            }
    }

    if(verify_email($email))
        {
        if(verify_email_dns($email))
            {
            if ($fName=='')
                {
            header('location:./contact.php?error=missing');
            }
                elseif ($email=='')
                {
                header('location:./contact.php?error=missing');
        }
                elseif ($message=='')
                {
            header('location:./contact.php?error=missing');
        }
                else
                {
            foreach ($myvars as $var)
                    {
                if (isset($_POST[$var]))
                        {
                    $var=$_POST[$var];
                }
            }

            $subject = "Email Submission for review"; 
                    $add.="test.email@gmail.com"; 
                $msg.="First Name:          \t$fName\n";
            $msg.="Email:               \t$email\n";
            $msg.="Topic:               \t$topic\n";
            $msg.="Message:             \t$message\n";
            $mailheaders="From: $email\n"; 
                $mailheaders.="Reply-To: $email\n"; 
            mail("$add", "$subject", $msg, $mailheaders);
            header('location:./contact.php?error=none');
        }//end else  
        }//end inner-if
            else
            {
            header('location:./contact.php?error=mx');
            }
    }// end outter-if

        else
        {
        header('location:./contact.php?error=format');
    }
    }// end starting if





    /** VIEW for form **/
 <form action="<?php echo $_SERVER['PHP_SELF']; ?>" method="post" name="contactForm"> 
     <label for="fName" class="first-name">Name:</label>
 <input type="text"  name="fName" value="" id="fName">
 <br><br>

 <label for="email" class="email-name">Email:</label>
 <input type="text"  name="email" value="" id="email">
 <br><br>

 <label for="topic" class="subject-name">Subject:</label>
 <input type="text"  name="topic" value="" id="topicsubject">
 <br><br>

 <label for="message" class="message-name">Message:</label>
 <textarea name="message"  rows="5" cols="60" id="message"></textarea>
 <br><br>

<input type="submit" name="submit" id="submit-btn"  class="submit-btn" value="Email Me">
 </form>





    /** USER FEEDBACK if error occurs **/

<?php
    $error=$_GET['error'];

        switch ($error) 
        {

            case "mx":
        echo "<br><span class='red'>Your email address you entered is invalid.  Please try again.</span><br>";
        break;

        case "format":
        echo "<br><span class='red'>Your email address is not in the correct format, it should look like name@domain.com. Please try again.</span><br>";
        break;

        case "missing":
        echo "<br><span class='red'>You seem to be missing a required field, please try again.</span><br>";
        break;

    case "none":
        echo "<br>Your email was sent.  I will get back to you as soon as I can.  Thank you for your interest.<br>";
    break;

    default:
        echo "<br><br>";
        }
?>

/**后端**/
您假设在访问页面时存在POST和GET变量。因此$_POST['submit']可能只在您实际提交表单时存在，否则您在第一次访问该页面时会出现错误

请尝试以下条件：

if(isset($_POST['submit']) ) {
    // now its safe to do something
}

在访问页面时，决不能假设任何$\u POST或$\u GET变量都可用

也离题：
在HTML中，您使用的“action”属性的url与您在此行中访问的页面的url相同：

<form action="<?php echo $_SERVER['PHP_SELF']; ?>" method="post" name="contactForm">

为了避免未定义的偏移错误，请在尝试访问偏移之前尝试检查是否存在偏移。这里的例子：我完全没有想到，这是一个简单而简单的解决方案。非常感谢你。
<form method="post" name="contactForm">