Ember – Add class on scroll to top

I’m trying to create a sticky header in an ember application. I just want to add a class to the <div id="stickyHeader"></div> via jquery when the user starts scrolling on the page. I squeezed the jquery into an action, but nothing happens...

I’m more a designer than a developer so pretty sure I oversee something fundametal here.

I have a <div></div> like this in my applications.hbs:

<div id="stickyHeader">
... some content ...
</div>

and an action in application.js:

...
actions: {
stickyHeaderClass: function(){
  this(window).scroll('addClassOnScroll')    
      var scroll = this(window).scrollTop();
      if (scroll >= 5) {
          return Ember.$('#stickyHeader').addClass('active');
      } else {
          return Ember.$('#stickyHeader').removeClass('active');
      }
},
....

I crapped the jquery stuff here. The rest is copy and paste ...

Any idea?