title: callback function when navigation element has a class "active" jquery plugin
body: <p>I'm using [ScrollIt][1] plugin which automatically adds an "active" class on an navigation element and  makes it easy to create paginated, feature vertically scrolling pages.</p>
  
  <p>I want to change the opacity of my navigation whenever the active class is not on an anchor element with the <code>href="#home"</code>.</p>
  
  <p>But I don't know how to check if the currently active item is the element which don't have this <code>href="#home"</code> and if is not that to add the opacity.</p>
  
  <p><strong>UPDATE WITH  WHAT I'VE TRIED:</strong></p>
  
  <pre><code>  function myCallBackFunction() {
      $('.navbar').css("opacity",this.is('[href="#home"]') ? 1 : 0);
      }
      var updateActive = function(ndx,myCallbackFunction) {
          if(settings.onPageChange &amp;&amp; ndx &amp;&amp; (active != ndx)) settings.onPageChange(ndx);
  
          active = ndx;
          $('[data-scroll-nav]').removeClass(settings.activeClass);
          $('[data-scroll-nav=' + ndx + ']').addClass(settings.activeClass);
          myCallbackFunction.call($('[data-scroll-nav=' + ndx + ']'));
      };
  </code></pre>
  
  <p>I get this error: <code>Uncaught TypeError: Cannot call method 'call' of undefined</code> </p>
  
  <p>Any suggestions on how I might do this ? </p>