How to scroll an element into view in native JavaScript using the scrollIntoView() method.

// ----------------------------------------------------------------------------
// How to Smooth Scroll to an Element with Native Javascript
//
// It is a commonly required to scroll to a particular section of a page upon a
// click. If scrolling happens via a smooth animation, then even better.
//
// Most websites use external scripts and plugins for this purpose, the reason
// being showing an animated scrolling was not natively supported.
//
// But things have changed now with the introduction of scrollIntoView() --- a
// native Javascript method that can scroll an element in the browser viewport.
// It supports smooth scrolling, and also you can customize the alignment of the
// element.
//
// https://usefulangle.com/post/156/javascript-scroll-to-element
// ----------------------------------------------------------------------------

// element which needs to be scrolled to
var element = document.querySelector("#post-container");

// scroll to element
element.scrollIntoView();

// NOTE: The scrollIntoView method scrolls with respect to the scrollable parent
// of the element. In usual cases, this means the browser window. But in cases
// where the element is contained within another scrollable element (element having
// a scrollbar), scrolling happens with respect to the parent and not the browser
// window.

//
// Customizing Scroll Behavior and Alignment with scrollIntoViewOptions
// Parameter
//
// The scrollIntoView method also accepts a parameter through which you can set
// an animated scroll behavior and also customize its alignment.
//
// This parameter scrollIntoViewOptions is an object with the following
// properties:
//
// behavior: This sets whether scrolling should be an animated one or an instant
// scroll to the element. It can have the following values...
//
//     - smooth : Does a smooth scrolling
//     - auto : Instant scrolling. This is the default value.
//
// block: This sets the vertical alignment of the shown element with respect to
// the scrollable parent. It can have the following values...
//
//     - start : Element is aligned at the top of the scrollable parent. This is
//       the default value.
//     - center : Element is aligned at the middle of the scrollable parent.
//     - end : Element is aligned at the bottom of the scrollable parent.
//     - nearest : This aligns the element suited to the current situation. If
//       user is currently above the element, it will be aligned at the bottom
//       of the scrollable parent. If user is currently below the element, it
//       will be aligned at the top. If is is already in view, nothing will
//       happen.
//
// inline: This sets the horizontal alignment of the shown element with respect
// to the scrollable parent. It can have the following values...
//
//     - start : Element is aligned at the left of the scrollable parent.
//     - center : Element is aligned at the middle of the scrollable parent.
//     - end : Element is aligned at the right of the scrollable parent.
//     - nearest : Aligns the element suited to the current situation. If user
//       is currently at the right of the element, it will be aligned at the
//       left of the scrollable parent. If user is currently at the left of the
//       element, it will be aligned at the right. Nothing happens if already in
//       view. This is the default value.

var element = document.querySelector("#post-container");

// smooth scroll to element and align it at the bottom
element.scrollIntoView({ behavior: "smooth", block: "end" });