title: PHP mail(); Send e-mail as plain text AND a HTML
body: <p>I've the following <strong>PHP</strong> code for sending e-mails with <strong>PHP mail() as HTML</strong>:</p>
  
  <pre><code>&lt;?php
      $to = "test@example.com";
  
      $subject = "This is the subject";
  
      $headers = "From: Me&lt;test@exapmle.com&gt;\r\n";
      $headers .= "Return-Path: test@exapmle.com\r\n";
      $headers .= "MIME-Version: 1.0\r\n";
      $headers .= "Content-Type: text/html; charset=utf-8\r\n";
      $headers .= "X-Priority: 1\r\n";
  
      $message = "This is my &lt;b&gt;message&lt;/b&gt;!";
  
      mail($to,$subject,$message,$headers);
  ?&gt;
  </code></pre>
  
  <p>But I want to support plain text and HTML. HTML for things like bold font and plain text to show <code>This is my message!</code> in non-html supporting email clients instead of <code>This is my &lt;b&gt;message&lt;/b&gt;!</code>.</p>
  
  <p>How can I do this?</p>
  
  <p>I read about boundary. Is that what I'm looking for? But if so, how to use it? I don't understand it.</p>