JS DOM: get window size (width height) (or viewport, display)

Find Viewport Size

View port is the area for displaying the HTML page. The result does not include scrollbar or toolbar nor status bar. Values changes when user zooms.

const x = document.documentElement.clientWidth;
const y = document.documentElement.clientHeight;

Find window size

Window size here includes the scroll bars, but does not include the URL field, tool bar, status bar, etc. Note: when user zooms in, these values decrease. Similarly when zoom out.

const x = window.innerWidth;
const y = window.innerHeight;

Find Display Resolution

This should be your display's resolution, unless you have operating system settings that make it 150% or other.

const x = screen.width;
const y = screen.height;

Find scroll amount

const x = window.pageXOffset;
const y = window.pageYOffset;

When no scroll, the value of window.pageYOffset is 0.

Find HTML document's rendered size

HTML element's size.

const x = document.documentElement.offsetWidth;
const y = document.documentElement.offsetHeight;