elementsFromPoint.js

//
// returns a list of all elements under the cursor
//
function elementsFromPoint(x,y) {
	var elements = [], previousPointerEvents = [], current, i, d;

        // get all elements via elementFromPoint, and remove them from hit-testing in order
	while ((current = document.elementFromPoint(x,y)) && elements.indexOf(current)===-1 && current != null) {
          
            // push the element and its current style
		elements.push(current);
		previousPointerEvents.push({
                value: current.style.getPropertyValue('pointer-events'),
                priority: current.style.getPropertyPriority('pointer-events')
            });
          
            // add "pointer-events: none", to get to the underlying element
		current.style.setProperty('pointer-events', 'none', 'important'); 
	}

        // restore the previous pointer-events values
	for(i = previousPointerEvents.length; d=previousPointerEvents[--i]; ) {
		elements[i].style.setProperty('pointer-events', d.value?d.value:'', d.priority); 
	}
      
        // return our results
	return elements;
}

No need to emulate document.elementsFromPoint() for Internet Explorer, as it have this method prefixed:

 document.msElementsFromPoint(x, y)