title: knockout.js and listen to check event on checkbox
body: <p>I'm trying to get a function to execute when a checkbox is checked or unchecked to verify all checkboxes are unchecked but it never gets executed.  I assume I'm not doing it correctly.</p>
  
  <pre><code>@Html.CheckBox("Subscription", new{ data_bind="disable: Disabled, checked: Checked, click: $parent.allSubscriptionsUnchecked"} ) 
  </code></pre>