/* Code for changing active link on clicking */
 var btns =
     $(".navbar-nav .nav-link");

 for (var i = 0; i < btns.length; i++) {
     btns[i].addEventListener("click",
         function() {
             var current = document
                 .getElementsByClassName("active");

             current[0].className = current[0]
                 .className.replace(" active", "");

             this.className += " active";
         });
 }

 /* Code for changing active 
 link on Scrolling */
 $(window).scroll(function() {
     var distance = $(window).scrollTop();
     $('.page-section').each(function(i) {

         if ($(this).position().top <=
             distance + 250) {

             $('.navbar-nav a.active')
                 .removeClass('active');

             $('.navbar-nav a').eq(i)
                 .addClass('active');
         }
     });
 }).scroll();