How to add smooth scrolling to Bootstrap's scroll spy function

Question

I\'ve been trying to add a smooth scrolling function to my site for a while now but can\'t seem to get it to work.

Here is my HTML code relating to my navigation:<

Answer 1

I combined it, and this is the results -

$(document).ready(function() {
     $("#toTop").hide();

            // fade in & out
       $(window).scroll(function () {
                    if ($(this).scrollTop() > 400) {
                        $('#toTop').fadeIn();
                    } else {
                        $('#toTop').fadeOut();
                    }
                });     
  $('a[href*=#]').each(function() {
    if (location.pathname.replace(/^\//,'') == this.pathname.replace(/^\//,'')
    && location.hostname == this.hostname
    && this.hash.replace(/#/,'') ) {
      var $targetId = $(this.hash), $targetAnchor = $('[name=' + this.hash.slice(1) +']');
      var $target = $targetId.length ? $targetId : $targetAnchor.length ? $targetAnchor : false;
       if ($target) {
         var targetOffset = $target.offset().top;
         $(this).click(function() {
           $('html, body').animate({scrollTop: targetOffset}, 400);
           return false;
         });
      }
    }
  });
});

I tested it and it works fine. hope this will help someone :)