title: knockout.js and disable custom binding
body: <p>I would like to bind disabled and css within a custom binding instead of using JQuery to assign a class and disabled it.  Can you do this within a custom binding without doing <code>$(element).attr('disabled', true).addClass('disabled');</code></p>
  
  <pre><code>data_bind="enabled: classroomId(), css: { 'disabled' : !classroomId() }"
  
  
  data_bind="disable: { !classroomId() }
  
  ko.bindingHandlers.disable = {
          update: function (element, valueAccessor) {
              var disabled = ko.utils.unwrapObservable(valueAccessor());
  
  
                   // Disable and Add Class to Button or Anchor Tag
  
          }
      };
  </code></pre>