Parallax effect whitespace : My parallax effect adds whitespace to the top when scrolling on page.

[No scroll,][1]
[When scrolling][2]

My JavaScript:

    <script>
	  $(window).scroll(function() {
	    var scrolledY = $(window).scrollTop();
	    $('.bg').css('background-position', 'left ' + ((scrolledY)) + 'px');
     });
    </script>


  [1]: https://i.stack.imgur.com/BBHw0.jpg
  [2]: https://i.stack.imgur.com/0VMUh.jpg