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

Another option if you're using Firefox is to use Greasemonkey scripts. Here's an example script which changes the main headline on cnn.com

If you're not familar with the Javascript coding needed to make Greasemoney scripts, you can use the Platypus add-on to edit the page in place and automatically generate a script file.