[jessfyi]

I always liked Lars Jung's implementation where the text is abstracted into blocks (which works on chrome) [0][1] and Rauno Freiberg's demo (uses -moz-element) where you can use it to pin sections, jump between them, and navigate the page in general [2].

[0] https://larsjung.de/pagemap/ [1] https://larsjung.de/pagemap/latest/demo/text.html [2] https://uiw.tf/minimap