title: Get select value in the same page
body: <p>I have this select button:</p>
  
  <pre><code>&lt;form method="post"&gt;
      &lt;label&gt;
          &lt;select id="label" name="challengeX" style="margin-top:150px;"&gt;
              &lt;option selected value="0"&gt; Global Statistics &lt;/option&gt;
              &lt;option value="1"&gt;Challenge 1&lt;/option&gt;
              &lt;option value="2"&gt;Challenge 2&lt;/option&gt;
              &lt;option value="3"&gt;Challenge 3&lt;/option&gt;
          &lt;/select&gt;
      &lt;/label&gt;
  &lt;/form&gt;
  </code></pre>
  
  <p>In the same page, few lines bellow, I have:</p>
  
  <pre><code>&lt;div id="challenge"&gt;
      &lt;?php
          $Ch = $_POST['challengeX']; 
          echo "Challenge: ".$Ch;
  
          showSomething($Ch,1,1);
      ?&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>But when I change the option, it didn't change the post value.</p>