How can I extract quadpoints and bbox of given text from a pdf?

[riya21793331bc32]

Am trying to highlight and add comments for given text in pdf, keeping this code as base 

https://codepen.io/practicalPDF/pen/OJMoGOY?editors=0010

But in the code, it takes input quadpoints and bbox.

How can i get quadpoints and bbox of a given text/sentence so as to highlight and add comment to them?

code language -> javascript

Help is needed asap.

thanks in advance!!!