title: PHP submit form without refreshing
body: <p>When the user submits the form, the result should be displayed without page refreshing. The PHP script is also in the same HTML page.</p>
  
  <p>What is wrong withe <code>$.post</code> jQuery?</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false">
  <div class="snippet-code">
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;!--
   Submit form without refreshing
  --&gt;
  
  &lt;html&gt;
  
  &lt;head&gt;
    &lt;title&gt;My first PHP page&lt;/title&gt;
    &lt;script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/2.1.3/jquery.min.js"&gt;&lt;/script&gt;
    &lt;script type="text/javascript" language="javascript"&gt;
      $(document).ready(function() {
        $("#btn").click(function(event) {
          var myname = $("#name").val();
          var myage = $("#age").val();
          $.post(
            "23.php", $("#testform").serialize()
          );
        });
      });
    &lt;/script&gt;
  &lt;/head&gt;
  
  &lt;body&gt;
    &lt;form action="&lt;?php echo $_SERVER['PHP_SELF']; ?&gt;" method="post" id="testform"&gt;
      &lt;!-- $_SERVER['PHP_SELF'] array --&gt;
      Name:
      &lt;input type="text" name="name" id="name" /&gt;Age:
      &lt;input type="text" name="age" id="age" /&gt;
      &lt;input type="submit" name="submit" id="btn" /&gt;
    &lt;/form&gt;
  &lt;/body&gt;
  
  &lt;/html&gt;</code></pre>
  </div>
  </div>
  </p>
  
  <pre><code>&lt;?php
      if ( isset($_POST['submit']) ) { // was the form submitted?
          echo "Welcome ". $_POST["name"] . "&lt;br&gt;";
          echo "You are ". $_POST["age"] . "years old&lt;br&gt;";
      }
  ?&gt;
  </code></pre>