title: HTML: Submit form on radio button check
body: <p>I have a form that displays two radio buttons (using PHP).</p>
  
  <pre><code>echo "&lt;form action=\"next.php\" method=\"post\"&gt;";
     echo "&lt;input type=\"radio\" name=\"paid\" value=\"0\" checked=\"checked\"&gt;No&lt;br&gt;";
     echo "&lt;input type=\"radio\" name=\"paid\" value=\"1\"&gt;Yes&lt;br&gt;";
  echo "&lt;/form&gt;";
  </code></pre>
  
  <p>One of the radio buttons is always checked by default.
  If the user checks the other radio button, I would like the form to submit itself (without the user having to click a submit button).</p>