title: why should we use if( $_SERVER["REQUEST_METHOD"] == "POST")
body: <p>I am watching a video about PHP form submit, it mentions this method </p>
  
  <pre><code>if ($_SERVER["REQUEST_METHOD"] == "POST") {
  /* code handle the form date */
  }
  </code></pre>
  
  <p>I don't know why we should use that? Can someone explain for me? Thanks!</p>