There is a website I found (see: http://genius.com/web-annotator) that can tell where in a webpage the user has clicked.  For instance, if you have a poem in your webpage:

Now listen to what the good book says

And it made good sense to me

Talking about reaping what you're sowing

And people trying to be free

And you don't know what "good book" means, then you can click on it.  and 'genius.com' knows that you've clicked on it (or highlighted it). 

How would you do this with Jquery?   I could see using scrolltop in some way, but I don't see how it is possible to get the exact words under the cursor.

Thanks.