title: please explain me - xmlhttp.open("GET","gethint.php?q="+str,true);
body: <p>In this code line:</p>
  
  <pre><code>xmlhttp.open("GET","gethint.php?q="+str,true);
  </code></pre>
  
  <p>what is the meaning of <code>gethint.php?q="+str</code> and why this is important?</p>