Browsers have "elementFromPoint", here is "nodeFromPoint" (including text-nodes) !

document.nodeFromPoint.js

/* Copyright (c) 2016 Tobias Buschor https://goo.gl/gl0mbf | MIT License https://goo.gl/HgajeK */

document.nodeFromPoint = function(x, y) {
	const el = document.elementFromPoint(x, y);
	const nodes = el.childNodes;
	for (let i = 0, node; node = nodes[i++];) {
		if (node.nodeType === 3) {
			const range = document.createRange();
			range.selectNode(node);
			const rects = range.getClientRects();
			for (let j = 0, rect; rect = rects[j++];) {
				if (x > rect.left && x < rect.right && y > rect.top && y < rect.bottom)
					return node;
			}
		}
	}
	return el;
};