title: Enable/Disable Submit Button based on radio buttons
body: <p>I have a form layed out like this: </p>
  
  <pre><code>&lt;form action="join-head-2-head.php" method="POST" enctype="application/x-www-form-urlencoded"&gt;
      &lt;table border="0" cellspacing="4" cellpadding="4"&gt;
          &lt;tr&gt;
            &lt;td colspan="2"&gt;&lt;input name="player1rules" type="radio" id="tandcy" value="y" /&gt;
            &lt;label for="tandcy"&gt;I  Have Reviewed The Rules And The Terms &amp;amp; Conditions And Agree To Abide By Them&lt;/label&gt;&lt;/td&gt;
        &lt;/tr&gt;
          &lt;tr&gt;
              &lt;td colspan="2"&gt;&lt;input name="player1rules" type="radio" id="tandcn" value="n" checked="checked" /&gt;&lt;label for="tandcn"&gt;I Do Not Agree To The Terms And Condtions And/Or Have Not Read The Rules&lt;/label&gt;&lt;/td&gt;
          &lt;/tr&gt;
          &lt;tr&gt;
              &lt;td width="100"&gt;&lt;input name="player1" type="hidden" value="&lt;? $session-&gt;username; ?&gt;" /&gt;&lt;/td&gt;
              &lt;td&gt;&lt;input type="submit" name="join" id="join" value="Take Available Slot" /&gt;&lt;/td&gt;
          &lt;/tr&gt;
      &lt;/table&gt;
  &lt;/form&gt;
  </code></pre>
  
  <p>What I am hoping to do is disable the submit button if id="tandcn" is selected, and enable it when id="tandcy". Is there an easy way to do that using javascript?</p>