httpWatch
firebug
fiddler
For these three packet capture tools, I use fiddler myself. As a performance test, a very important skill in the use of packet capture tools
There are already many people on the Internet who have talked about the use and installation of fiddler, so I won't talk about it.
The main emphasis here is that as a performance tester, you also need to have a good understanding of HTTP. So you need to study hard.