title: double submission when refresh php
body: <p>I'm trying to correct the issue of double submit in my script. When I press submit it only updates mysql once(which is what I want).  However, when I hit refresh it updates mysql again.  It seems to ignore the if statement once the refresh button is hit.  What would I do to stop this </p>
  
  <p>here is my code</p>
  
  <pre><code>if (isset($_POST['submitButton'])) { 
  //do something
   }
  
  
  &lt;form action = "table.php" method="post"&gt;
  &lt;label for="submitButton"&gt;&lt;/label&gt;
  &lt;input type="submit" name="submitButton" id="submitButton"
  value="Submit Form"/&gt;
  &lt;/form&gt;
  </code></pre>