Hey! Before you go too far down the rabbit hole of JavaScript-based smooth scrolling, know that there is a native CSS feature for this: scroll-behavior.
html {
scroll-behavior: smooth;
}
And before you reach for a library like jQuery to help, there is also a native JavaScript version of smooth scrolling, like this:
// 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'
});
Dustan Kasten has a polyfill for this. And you’d probably only reach for this if you were doing something with scrolling the page that couldn’t be done with target jump links and CSS.
Whatever technology you use for smooth scrolling, accessibility is a concern. For example, if you click a ` hash` link, the native behavior is for the browser to change focus to the element matching that ID. The page may scroll, but the scrolling is a side effect of the focus changing.If you override the default focus-changing behavior (which you have to, to prevent instant scrolling and enable smooth scrolling), you need to handle the focus-changing yourself. Heather Migliorisi wrote about this, with code solutions, in Smooth Scrolling and Accessibility. jQuery can also do this. Here’s the code to perform a smooth page scroll to an anchor on the same page. It has some logic built in to identify those jump links, and not target other links.
// Select all links with hashes
$('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
};
});
}
}
});
If you’ve used this code and you’re all like HEY WHAT’S WITH THE BLUE OUTLINES?!, read the stuff about accessibility above. James Quick has a nice step-by-step tutorial on how to implement smooth scrolling in React using the react-scroll plugin: Defines which position on the element being positioned to align with the target element: "horizontal vertical" alignment. A single value such as "right" will be normalized to "right center", "top" will be normalized to "center top" (following CSS convention). Acceptable horizontal values: "left", "center", "right". Acceptable vertical values: "top", "center", "center"`1. Example: "center"2 or "center"3. Each dimension can also contain offsets, in pixels or percent, e.g., "center"`4. Percentage offsets are relative to the element being positioned. - at (default:
"center")
Defines which position on the target element to align the positioned element against: "horizontal vertical" alignment. See the option for full details on possible values. Percentage offsets are relative to the target element. - of (default:
"center"`7)
Which element to position against. If you provide a selector or jQuery object, the first matching element will be used. If you provide an event object, the "center"8 and "center"9 properties will be used. Example: "right"`0 - collision (default:
"right"`1)
When the positioned element overflows the window in some direction, move it to an alternative position. Similar to and , this accepts a single value or a pair for horizontal/vertical, e.g., "right"1, "right"5, "right"6, "right"`7. - `"right"`1: Flips the element to the opposite side of the target and the collision detection is run again to see if it will fit. Whichever side allows more of the element to be visible will be used.
- `"right"`5: Shift the element away from the edge of the window.
- `"right center"`0: First applies the flip logic, placing the element on whichever side allows more of the element to be visible. Then the fit logic is applied to ensure as much of the element is visible as possible.
- `"right center"`1: Does not apply any collision detection.
- using (default:
"center"`7)
When specified, the actual property setting is delegated to this callback. Receives two parameters: The first is a hash of "right center"3 and "right center"4 values for the position that should be set and can be forwarded to "right center"5 or "right center"6.
The second provides feedback about the position and dimensions of both elements, as well as calculations to their relative position. Both "right center"7 and "right center"8 have these properties: "right center"8, "right center"4, "right center"3, "top"2, "top"3. In addition, there's "top"4, "top"5 and "top"6, giving you twelve potential directions like "top"`7. - within (default: `"top"`8)
Element to position within, affecting collision detection. If you provide a selector or jQuery object, the first matching element will be used.
The jQuery UI `"top"`9 method allows you to position an element relative to the window, document, another element, or the cursor/mouse, without worrying about offset parents. Note: jQuery UI does not support positioning hidden elements. This is a standalone jQuery plugin and has no dependencies on other jQuery UI components. This plugin extends jQuery's built-in "top"`9 method. If jQuery UI is not loaded, calling the "top"`9 method may not fail directly, as the method still exists. However, the expected behavior will not occur. Changing the position of a scrollbar using CSS is a simple process that can be done by creating a new class for the element, targeting the scrollbar and the thumb, and then using the "position" property to change the position of the scrollbar. Guidance. Scroll view is a container control that enables scrolling in the window, when content is larger than the viewport.. Place your content in a scroll view when your window has limited viewport space, e.g. long list / tree views or modals.. Scroll views can have vertical and horizontal scrollbars.. | 
