Intercept an HTTP request at browser end to alter some html content

Question

I would like to do as follows. What would be the best way? A general answer will also be fine.

I would like to intercept an HTTP request at the client end to alter some

Answer 1

you can come to China ^_^ censorship like this is everywhere, you don't have to implement your own.

Ok, that is a joke, the answer is you can implement browser plugins for such kind of tasks. or maybe you need to implement a ROUTING filter ( GFW like ) on the router.