title: How to fix "XML parsing error: incomprehensible data after the document element"?
body: <p>I work locally on WAMP and the JS doesn't work. When I click on a button, I get this error in the console.</p>
  
  <p>I've searched the Internet a lot without finding an answer.</p>
  
  <p>Here is the console error :</p>
  
  <pre><code>XML parsing error: incomprehensible data after the document element
  Location : http://.../index.php
  Line number 2, column
  </code></pre>
  
  <p>Here is the code  index.php:2:1</p>
  
  <pre><code>&lt;?php
  include('./header.php');
  if ($_POST){
      $password=$_POST["password"];
      $sql=mysql_query("SELECT * FROM users WHERE password='$password'");
  </code></pre>
  
  <p>I'd like the JS to work.</p>
  
  <p>Do you have a solution? </p>
  
  <p>Thank you in advance :)</p>