以我为例，这封电子邮件发送得很好，但却很难收到，因为整个信息在一行中超过998个字符。我需要使用以下行使最大长度为70的行:wordwrap($email_message, 70， "\r\n");。

https://www.rfc-editor.org/rfc/rfc5322#section-2.1.1

该规范对一行中的字符数量有两个限制。每行字符必须不超过998个字符，不超过78个字符，不包括CRLF字符。

如果您正在使用SMTP配置来发送电子邮件，请尝试使用PHPMailer。您可以从https://github.com/PHPMailer/PHPMailer下载该库。

我用这种方式创建了我的电子邮件:

function send_mail($email, $recipient_name, $message='')
{
    require("phpmailer/class.phpmailer.php");

    $mail = new PHPMailer();

    $mail->CharSet = "utf-8";
    $mail->IsSMTP();                                      // Set mailer to use SMTP
    $mail->Host = "mail.example.com";  // Specify main and backup server
    $mail->SMTPAuth = true;     // Turn on SMTP authentication
    $mail->Username = "myusername";  // SMTP username
    $mail->Password = "p@ssw0rd"; // SMTP password

    $mail->From = "me@walalang.com";
    $mail->FromName = "System-Ad";
    $mail->AddAddress($email, $recipient_name);

    $mail->WordWrap = 50;                                 // Set word wrap to 50 characters
    $mail->IsHTML(true);                                  // Set email format to HTML (true) or plain text (false)

    $mail->Subject = "This is a Sampleenter code here Email";
    $mail->Body    = $message;
    $mail->AltBody = "This is the body in plain text for non-HTML mail clients";
    $mail->AddEmbeddedImage('images/logo.png', 'logo', 'logo.png');
    $mail->addAttachment('files/file.xlsx');

    if(!$mail->Send())
    {
       echo "Message could not be sent. <p>";
       echo "Mailer Error: " . $mail->ErrorInfo;
       exit;
    }

    echo "Message has been sent";
}

在邮件功能中添加邮件头。

$header = "From: noreply@example.com\r\n";
$header.= "MIME-Version: 1.0\r\n";
$header.= "Content-Type: text/html; charset=ISO-8859-1\r\n";
$header.= "X-Priority: 1\r\n";

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

if($status)
{
    echo '<p>Your mail has been sent!</p>';
} else {
    echo '<p>Something went wrong. Please try again!</p>';
}

我觉得这个应该能搞定。我只是添加了一个if(isset，并在主体中的变量中添加了连接，以将PHP与HTML分开。

<?php
    $name = $_POST['name'];
    $email = $_POST['email'];
    $message = $_POST['message'];
    $from = 'From: yoursite.com'; 
    $to = 'contact@yoursite.com'; 
    $subject = 'Customer Inquiry';
    $body = "From:" .$name."\r\n E-Mail:" .$email."\r\n Message:\r\n" .$message;

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

?>

以我为例，这封电子邮件发送得很好，但却很难收到，因为整个信息在一行中超过998个字符。我需要使用以下行使最大长度为70的行:wordwrap($email_message, 70， "\r\n");。

https://www.rfc-editor.org/rfc/rfc5322#section-2.1.1

该规范对一行中的字符数量有两个限制。每行字符必须不超过998个字符，不超过78个字符，不包括CRLF字符。

如果使用PHP发送邮件遇到问题，可以考虑使用PHPMailer或SwiftMailer等替代方案。

当我需要用PHP发送邮件时，我通常使用SwiftMailer。

基本用法:

require 'mail/swift_required.php';

$message = Swift_Message::newInstance()
    // The subject of your email
    ->setSubject('Jane Doe sends you a message')
    // The from address(es)
    ->setFrom(array('jane.doe@gmail.com' => 'Jane Doe'))
    // The to address(es)
    ->setTo(array('frank.stevens@gmail.com' => 'Frank Stevens'))
    // Here, you put the content of your email
    ->setBody('<h3>New message</h3><p>Here goes the rest of my message</p>', 'text/html');

if (Swift_Mailer::newInstance(Swift_MailTransport::newInstance())->send($message)) {
    echo json_encode([
        "status" => "OK",
        "message" => 'Your message has been sent!'
    ], JSON_PRETTY_PRINT);
} else {
    echo json_encode([
        "status" => "error",
        "message" => 'Oops! Something went wrong!'
    ], JSON_PRETTY_PRINT);
}

有关如何使用SwiftMailer的更多信息，请参阅官方文档。