title: .is(':checked') not working in jquery
body: <p>Hello friends I want when user checked the radio box then the text will show following is my code you can also check my code here <a href="http://jsfiddle.net/mY4N5/" rel="nofollow">http://jsfiddle.net/mY4N5/</a></p>
  
  <p><strong>HTML</strong></p>
  
  <pre><code>&lt;form id="form1" name="form1" method="post" action=""&gt;
    &lt;label&gt;
    &lt;input name="radiobutton" type="radio" value="radiobutton" id="red"/&gt;
    &lt;/label&gt;
  &lt;/form&gt;
  &lt;div id="dis"&gt;
  hi
  
  &lt;/div&gt;
  </code></pre>
  
  <p>Script</p>
  
  <pre><code>$('#dis').css('display','none');
  
      if($('#red').is(':checked'))
      {
      $('#dis').css('display','block');
      }
      else
      {
          $('#dis').css('display','none');
      };
  </code></pre>