Get HTML element position relative to document space

get_html_element_coords.js

function getElementCoordinates(el) {
	const doc = document.documentElement;
	const scrollLeft = window.pageXOffset || doc.scrollLeft;
	const scrollTop = window.pageYOffset || doc.scrollTop;
	const rect = el.getBoundingClientRect();
	return {
		top: rect.top + scrollTop,
		left: rect.left + scrollLeft
	}
}