title: xhttp.send() command, "blocked by CORS policy: Cross origin requests are only supported ..." etc
body: <p>The following lines of code in a JS function, were working perfectly well. However, the <code>send()</code> method, suddenly produced the error below, and can't link in to my <code>localhost</code> DB ...</p>
  
  <pre><code>  xhttp.open("GET", "connect_db.php?q="+str, true);
    xhttp.send();
  </code></pre>
  
  <p>The error from console log, in full, is: </p>
  
  <blockquote>
    <p>Access to XMLHttpRequest at
    'file:///Users/liamjf/.bitnami/stackman/machines/xampp/volumes/root/htdocs/selectQuery.php?q=eu'
    from origin 'null' has been blocked by CORS policy: Cross origin
    requests are only supported for protocol schemes: http, data, chrome,
    chrome-extension, https</p>
  </blockquote>