Make selections and change the content to see the difference between text mappings and HTML mappings. View the source to see one further complication, that parsed DOM does not match HTML strings! (Hint: the browser gives no access to the original HTML producing the page)

My bonny lies over the ocean 🌊.
My bonny lies over the sea 🌊.
My bonny lies over the ocean 🌊.
So bring back my bonny to youme.

Offsets in the raw text of the serialized HTML output. 



Offsets mapped into the text nodes of the serialized HTML output.



Void meta tags inserted as marker positions.