Well, the solution depends on the type of problem, I use the javascript animate method for the button click. and I use codes from bellow links for the navbar
https://css-tricks.com/snippets/jquery/smooth-scrolling/
$(document).ready(function () {
$(".js--scroll-to-plans").click(function () {
$("body,html").animate(
{
scrollTop: $(".js--section-plans").offset().top,
},
1000
);
return false;
});
$(".js--scroll-to-start").click(function () {
$("body,html").animate(
{
scrollTop: $(".js--section-features").offset().top,
},
1000
);
return false;
});
$('a[href*="#"]')
// Remove links that don't actually link to anything
.not('[href="#"]')
.not('[href="#0"]')
.click(function(event) {
// On-page links
if (
location.pathname.replace(/^\//, '') == this.pathname.replace(/^\//, '')
&&
location.hostname == this.hostname
) {
// Figure out element to scroll to
var target = $(this.hash);
target = target.length ? target : $('[name=' + this.hash.slice(1) + ']');
// Does a scroll target exist?
if (target.length) {
// Only prevent default if animation is actually gonna happen
event.preventDefault();
$('html, body').animate({
scrollTop: target.offset().top
}, 1000, function() {
// Callback after animation
// Must change focus!
var $target = $(target);
$target.focus();
if ($target.is(":focus")) { // Checking if the target was focused
return false;
} else {
$target.attr('tabindex','-1'); // Adding tabindex for elements not focusable
$target.focus(); // Set focus again
};
});
}
}
});
});