What is anchorNode , baseNode , extentNode and focusNode in the object returned by document.getSelection?

Question

If I make a selection in a html page and I do :

var a = document.getSelection()

I get an object with four properties :

1. anchorNod

Answer 1

I'm by no means an expert, but by experimenting it seems to me that the anchorNode is the node the selection started on and focusNode the one where it ended (presumably because it has focus once the selection is over).

baseNode seems to be the same as anchorNode and extentNode the same as baseNode, only that they don't exist in Firefox, only in Chrome.