title: How to reset/block $_POST reset by backwards of browser
body: <p>I'm trying to create a quiz with Form submit and $_POST.</p>
  <p><strong>Step 1.</strong> User should verify with e-mail first and then can play quiz.</p>
  <p><strong>Step 2-a.</strong> If user select correct answer, then user will be send to next-quiz-page.php.</p>
  <p><strong>Step 2-b.</strong> If it's wrong, then user will be send to failed-page.php.</p>
  <p><strong>Step 3.</strong> The status will be saved in database, when they win or lose. Therefore user who already played, can not play it again.</p>
  <p>I did it until here with this method $_POST:</p>
  <pre><code>if ( isset( $_POST['quiz_start']) ) {
  // quiz start
  } else {
  // quiz can not be loaded
  }
  </code></pre>
  <p>Here is the problem:
  when i click a &quot;backwards&quot; in <strong>Step 2</strong>(next-quiz-page.php, failed-page.php) of browser, then i can back to the quiz-page again and i can play quiz again. Because the value of $_POST still are there. Of course when i submit, i will get error message because the database already has the data which is already &quot;played&quot;.</p>
  <p>Is there any way to reset $_POST by clicking backwards of browsers?</p>