php邮件脚本，允许用户定义电子邮件将发送到的目标地址

OK, so I've got a basic form and email script that I wrote for for a website contact form. For another purpose, I would like to modify this script to, from the contact form, allow the user to define where the email will be sent to. I've tried several methods out there and haven't had any luck.

HTML:

<form action='/mail.php' id='contact-form' method='post'>
  <p>
    <label for='cf_name'>Name to send emails as *</label>
      <input id='cf_name' name='cf_name' placeholder='Enter your "name"...' required='required' title='Name' type='text' />
  </p>
  <p>
    <label for='cf_email'>Email address to be sent to *</label>
      <input id='cf_email' name='cf_email' placeholder='Email address...' required='required' title='Email address' type='email' />
  </p>
  <p>
  <label for='cf_subject'>Message Title *</label>
    <input id='cf_subject' name='cf_subject' placeholder='Email Subject...' required='required' title='Email Subject' type='text' />
  </p>
  <p>
    <label for='cf_message'>Message *</label>
      <textarea id='cf_message' name='cf_message' placeholder='Message text...' required='required' rows='10' title='Message text'></textarea>
  </p>
  <p>
    <input type='submit' value='Send message' />
  </p>
</form>

And the current semi-edited PHP:

<?php

// Destination email address
define('EMAIL_DEST', 'abc@123.com');

// Contact form error message
define('ERROR_MESSAGE', 'Something went wrong, please try to submit later.');

// Contact form message title
define('CONTACT_EMAIL_TITLE', '');

// Contact form success message
define('CONTACT_SUCCESS_MESSAGE', 'Thank you! We will get back to you as soon as possible.');


// Variables assignment
$name         = isset($_POST['cf_name']) ? $_POST['cf_name'] : '';
$email        = isset($_POST['cf_email']) ? $_POST['cf_email'] : '';
$subject      = isset($_POST['cf_subject']) ? $_POST['cf_subject'] : '';
$message      = isset($_POST['cf_message']) ? $_POST['cf_message'] : '';


// Send email if required fields are filled
if(!empty($name) && !empty($email) && !empty($subject) && !empty($message)) {
    // Headers
    $headers  = 'MIME-Version: 1.0' . "
";
    $headers .= 'Content-type: text/html; charset=utf-8' . "
";
    $headers .= 'From: ' . $name;

// Message title
$message_title = CONTACT_EMAIL_TITLE;

// Message
$message_body = "$message";

// Send mail
mail(EMAIL_DEST, $message_title, $message_body, $headers);


// Show success message
echo '<div class="box-success round-3"><div class="box-content"><p>' . CONTACT_SUCCESS_MESSAGE . '</p></div></div>';
exit;
} else {
    // Show error message
    echo '<div class="box-error round-3"><div class="box-content"><p>' . ERROR_MESSAGE . '</p></div></div>';
    exit;
}

You are defining

/ Destination email address
define('EMAIL_DEST', 'abc@123.com');

and then send the email to this adress via :

// Send mail
mail(EMAIL_DEST, $message_title, $message_body, $headers);

So if you want to send the email to the provided email adress just use

// Send mail
mail($email, $message_title, $message_body, $headers);

Because the email adress is already defined:

$email = isset($_POST['cf_email']) ? $_POST['cf_email'] : '';

i don't know what is EMAIL_DEST here..You must have defined it somewhere .

if you look at mail function

bool mail ( string $to , string $subject , string $message [, string $additional_headers [, string $additional_parameters ]] )

the first string is for to here,

so, i am pretty sure you need to add $email instead of EMAIL_DEST in mail function, to send it to that particular user

 mail($email , $message_title, $message_body, $headers);

I think the issue is with your Mail Header

// Headers
$headers  = 'MIME-Version: 1.0' . "
";
$headers .= 'Content-type: text/html; charset=utf-8' . "
";
$headers .= 'From: ' . $email;

The From in your Mail Header should be an email address rather than of name.

Or you can specify the name if you like in this way

$headers .= 'From: ' . $name . '<' .$email. '>'; //From: Birthday Reminder <birthday@example.com>

EDIT

BUT You also need to specify the $to parameter in the mail function like other says

mail($email , $subject, $message, $headers);