努力使联系表格工作（HTML5 / PHP）

I'm having some difficulty getting my contact form working on my website. Whenever I try submit, it opens index.php, a blank page, rather than actually executing the script and firing off an email.

Here's the form.

    <form method="post" action="index.php">
        <div class="field">
            <label for="name">Name</label>
            <input type="text" name="name" id="name" />
        </div>
        <div class="field">
            <label for="email">Email</label>
            <input type="email" name="email" id="email" />
        </div>
        <div class="field">
            <label for="message">Message</label>
            <textarea name="message" id="message" rows="4"></textarea>
        </div>
        <ul class="actions">
            <li><input type="submit" type="submit" value="Send Message" /></li>
        </ul>
    </form>

Here's the index.php file I'm using.

<?php
$name = $_POST['name'];
$email = $_POST['email'];
$message = $_POST['message'];
$from = 'From: Test'; 
$to = 'brett@edge.yt'; 
$subject = 'Hello';

$body = "From: $name
 E-Mail: $email
 Message:
 $message";

if ($_POST['submit']) {
  if (mail ($to, $subject, $body, $from)) { 
    echo '<p>Your message has been sent!</p>';
  } else { 
    echo '<p>Something went wrong, go back and try again!</p>'; 
  }
}
?>

PHP is seemingly properly installed on my server, I can use a PHPInfo() file no problem.

The email will never try to send because $_POST['submit'] is not set. You don't have a control on your form named submit. If you intended that to be the submit button, you need to give it a name attribute.

<input type="submit" name="submit" value="Send Message" />

Then, in your PHP script, check that submit isset rather than just evaluating it as a boolean.

if (isset($_POST['submit'])) { ...

That way, if the form hasn't been submitted you won't get an undefined index notice.