Adding easing to jquery css swap

Adding easing to jquery css swap

HI I am trying to add some easing to a script I'm am working on and I can't get it to work right.

var $mainlogo = jQuery('#mainlogo'); var $menuback = jQuery('.x-navbar'); jQuery(document).scroll(function() { $mainlogo.css({display: jQuery(this).scrollTop()>170 ? "block":"none"}); $menuback.css({background: jQuery(this).scrollTop()>170 ? "rgba( 255, 255, 255, 0.7 )":"none"}, { easing: 'swing', duration: '2000' }); });

What Am I doing wrong? I just want it to fade in instead of an immediate appearance.

Do I need to use something like

  1.  .fadeTo()