Calculating text selection offsets in nest elements in Javascript

Question

The Problem

I am trying to figure out the offset of a selection from a particular node with javascript.

Say I have the following HTML

Answer 1

you can use the following java script code:

var text = window.getSelection();
var start = text.anchorOffset;
alert(start);
var end = text.focusOffset - text.anchorOffset;
alert(end);