Smooth scrolling when clicking an anchor link

Update April 2018: There’s now a native way to do this:

document.querySelectorAll('a[href^="#"]').forEach(anchor => {
    anchor.addEventListener('click', function (e) {
        e.preventDefault();

        document.querySelector(this.getAttribute('href')).scrollIntoView({
            behavior: 'smooth'
        });
    });
});

This is currently only supported in the most bleeding edge browsers.

For older browser support, you can use this jQuery technique:

$(document).on('click', 'a[href^="#"]', function (event) {
    event.preventDefault();

    $('html, body').animate({
        scrollTop: $($.attr(this, 'href')).offset().top
    }, 500);
});

And here’s the fiddle: http://jsfiddle.net/9SDLw/

If your target element does not have an ID, and you’re linking to it by its name, use this:

$('a[href^="#"]').click(function () {
    $('html, body').animate({
        scrollTop: $('[name="' + $.attr(this, 'href').substr(1) + '"]').offset().top
    }, 500);

    return false;
});

For increased performance, you should cache that $('html, body') selector, so that it doesn’t run every single time an anchor is clicked:

var $root = $('html, body');

$('a[href^="#"]').click(function () {
    $root.animate({
        scrollTop: $( $.attr(this, 'href') ).offset().top
    }, 500);

    return false;
});

If you want the URL to be updated, do it within the animate callback:

var $root = $('html, body');

$('a[href^="#"]').click(function() {
    var href = $.attr(this, 'href');

    $root.animate({
        scrollTop: $(href).offset().top
    }, 500, function () {
        window.location.hash = href;
    });

    return false;
});