title: cannot unhide/hide table row based on a checkbox.
body: <p>I have a form working where changing the value of a dropdown will hide or display a row.  What I can't get working is trying to hide or unhide a row based on a checkbox. </p>
  
  <p>My Javascript_tag is </p>
  
  <pre><code>&lt;%= javascript_tag do %&gt;
          $(document).ready(function(){
    //     if($("#observation_discussed_with_employee").is('checked'){
                $(".hidden_option_date_discussed").fadeIn('slow');
                alert("test");
      //     }
           });
   &lt;% end %&gt;
  </code></pre>
  
  <p>The style_add.css is</p>
  
  <pre><code>.hidden_option{
      display: none;
  }
  
  .hidden_option_date_discussed{
      display: none;
  }
  </code></pre>
  
  <p>I have that stylesheet linked with <code>&lt;%= stylesheet_link_tag "style_adds" %&gt;</code> (the other hide/show works so I know I am able to use this stylesheet</p>
  
  <p>The checkbox field and the subsequent field I want to hide/unhide is below</p>
  
  <pre><code>    &lt;tr&gt;
                &lt;div id="discussed"&gt;
                  &lt;td&gt;&lt;%= f.label :discussed_with_employee %&gt;&lt;/td&gt;
                  &lt;td&gt;&lt;%= f.check_box :discussed_with_employee  %&gt;&lt;/td&gt;
                &lt;/div&gt;
          &lt;/tr&gt;
  
          &lt;tr class="hidden_option_date_discussed"&gt;
  </code></pre>
  
  <p>If I run the page with the if statements remarked out as shown, I get the alert box. However, if I unremark the if statements, then I don't see an alert. </p>
  
  <pre><code>        &lt;div class="field" &gt;
            &lt;td&gt;&lt;%= f.label :date_discussed %&gt;&lt;/td&gt;
            &lt;td&gt;&lt;%= f.date_select( :date_discussed,  :default =&gt; 0.days.from_now, min: 1.year.ago) %&gt;&lt;/td&gt;
          &lt;/div&gt;
  &lt;/tr&gt;
  </code></pre>