how to smooth scroll in html code example

Example 1: smooth scroll css

html {
  scroll-behavior: smooth;
}

/* No support in IE, or Safari
You can use this JS polyfill for those */
http://iamdustan.com/smoothscroll/

Example 2: smooth scroll

// Scroll to specific values
// scrollTo is the same
window.scroll({
  top: 2500, 
  left: 0, 
  behavior: 'smooth'
});

// Scroll certain amounts from current position 
window.scrollBy({ 
  top: 100, // could be negative value
  left: 0, 
  behavior: 'smooth' 
});

// Scroll to a certain element
document.querySelector('.hello').scrollIntoView({ 
  behavior: 'smooth' 
});

Example 3: smooth scroll

/* ==========================================================================
   Smooth scroll
   ========================================================================== */
$('a[href*=#]:not([href=#])').on('click', function() {
    if (location.pathname.replace(/^\//, '') === this.pathname.replace(/^\//, '') && location.hostname === this.hostname) {
        var target = $(this.hash);
        target = target.length ? target : $('[name=' + this.hash.slice(1) + ']');
        if (target.length) {
            $('html,body').animate({

                scrollTop: (target.offset().top - 40)
            }, 1000);
            return false;
        }
    }
});

Example 4: scroll smooth css

html {
  scroll-behavior: smooth;
}