I am trying to fix "Navbar" just after "Header" smoothly which is 50px from top.

DEMO LINK

jQuery:

$(document).ready(function() {
       $(window).bind('scroll', function() {
       var navHeight = $( window ).height() - 80;
             if ($(window).scrollTop() > navHeight) {
                 $('.navigation').addClass('fixed');
             }
             else {
                 $('.navigation').removeClass('fixed');
             }
        });
    });