title: how to perform events when a checkbox is checked/unchecked in jquery
body: <p>I have the following jquery code which works fine. </p>
  
  <pre><code>$('#onlyTwo').click(function() {
                  $("#textarea3").attr("disabled", true);
                  $("#textarea4").attr("disabled", true);
                  $("#radio3").attr("disabled", true);
                  $("#radio4").attr("disabled", true);
                  return true;
              });
  </code></pre>
  
  <p>This is making some fields disabled when 'onlyTwo' checkbox is clicked.  How can i make these fields enabed again when 'onlyTwo' checkbox is unchecked...</p>
  
  <p>basically i want to know how to find out whether a checkbox is checked or not</p>