title: HTML Input Radio Value="false" Posts NULL
body: <p>In FireFox, I have a radio input with it's value set to the string "false" (not sure if there's any possible distinction from boolean false).  </p>
  
  <pre><code>&lt;input name="test_1" type="radio" value="false" /&gt;
  </code></pre>
  
  <p>When I post the form, I get:</p>
  
  <pre><code>print_r($_POST["test_1"]);
  
  Array
  (
      [test_1] =&gt;
  )
  </code></pre>
  
  <p>Which suggests that the browser casts the string "false" to Boolean FALSE or NULL.</p>
  
  <ol>
  <li><p>What is the expected behavior?</p></li>
  <li><p>What if I specifically want the string "false" to be returned?</p></li>
  </ol>