php邮件需要配置才能工作吗？

Question

I'm trying to do a very simple mail form in PHP but get the error:

PHP Notice: Undefined index: in /var/www/html/sites/send_contact.php on line 10, referer: http://example.com/contact2.php

My PHP file looks like this:

<?php // send_contact.php
// Contact subject
$subject =$_POST["$subject"]; 
// Details
$message=$_POST["$detail"];

// Mail of sender
$mail_from=$_POST["$customer_mail"]; 
// From 
$name2=$_POST["$name2"];

$header="From: $mail_from\r\n";

// Enter your email address
$to="joe@mail.com";

$send_contact=mail($to,$subject,$message,$header);

// Check, if message sent to your email 
// display message "We've recived your information"
if($send_contact){
echo "We've recived your contact information";
}
else {
echo "ERROR";
}
?>

Answer 1

The easiest guess is that you're doing a mistake accessing your variables.

instead of:

$name2=$_POST["$name2"];

use this:

$name2=$_POST["name2"];

Or, if you know the difference and are doing this on purpose, make sure your $name2 variable is defined with the correct name of the HTML form field.

As an aside, I would strongly recommend using a library like PHPMailer to send emails.
Your example is quite simple and the mail() should work just fine, but for anything more elaborate (ie. having attachments or html) or needing to send using an external mail server by SMTP (with or without authentication), it will do a much better job and save you lots of time.

For a better idea, check this example from their website:

require_once('../class.phpmailer.php');
$mail = new PHPMailer(true); // the true param means it will throw exceptions on     errors, which we need to catch

$mail->IsSMTP(); // telling the class to use SMTP

try {
  $mail->Host       = "mail.yourdomain.com"; // SMTP server
  $mail->SMTPDebug  = 2;                     // enables SMTP debug information (for testing)
  $mail->SMTPAuth   = true;                  // enable SMTP authentication
  $mail->Host       = "mail.yourdomain.com"; // sets the SMTP server
  $mail->Port       = 26;                    // set the SMTP port for the GMAIL server
  $mail->Username   = "yourname@yourdomain"; // SMTP account username
  $mail->Password   = "yourpassword";        // SMTP account password
  $mail->AddReplyTo('name@yourdomain.com', 'First Last');
  $mail->AddAddress('whoto@otherdomain.com', 'John Doe');
  $mail->SetFrom('name@yourdomain.com', 'First Last');
  $mail->AddReplyTo('name@yourdomain.com', 'First Last');
  $mail->Subject = 'PHPMailer Test Subject via mail(), advanced';
  $mail->AltBody = 'To view the message, please use an HTML compatible email viewer!';     // optional - MsgHTML will create an alternate automatically
  $mail->MsgHTML(file_get_contents('contents.html'));
  $mail->AddAttachment('images/phpmailer.gif');      // attachment
  $mail->AddAttachment('images/phpmailer_mini.gif'); // attachment
  $mail->Send();
  echo "Message Sent OK<p></p>\n";
} catch (phpmailerException $e) {
  echo $e->errorMessage(); //Pretty error messages from PHPMailer
} catch (Exception $e) {
  echo $e->getMessage(); //Boring error messages from anything else!
}

Answer 2

The error is telling you exactly what is wrong:

Line 10:

$name2=$_POST["$name2"];

You are using '$name2' before it is defined.

PHP can substitute variables in strings:

$var1 = "bar";
echo "foo $var1"; // prints "foo bar"

In your HTML use something similar to the following:

<input type="...whatever..." name="name2" />

Then in PHP, assuming the data was POSTed, you would access it using:

$name2 = $_POST["name2"];

Answer 3

It seems that your code doesn't pass the $_POST data as you expect. I recommend you to check the keys of $_POST as follows:

<?php
print_r(array_keys($_POST));
?>

If it doesn't display the value of $name2, it means you should modify the web page sending form data to send_contact.php.