title: Setting $_POST variables
body: <p>I have a form using POST, and a variable.
  How would I set that variable in $_POST so that after the form is submitted, I can still get the variable?</p>
  
  <p>I tried just</p>
  
  <pre><code>$_POST['variable'] = $variable;
  </code></pre>
  
  <p>It ends up empty.</p>