Rated 1 out of 5 stars

Firebug's Net Panel is a better choice than HttpFox. Net Panel includes additional features: a graphical chart, markers for DomContentLoaded on onload events, and automatically clearing when a new page is loaded. However, both Net Panel and HttpFox suffer from the same problem: they run in the same (single-threaded) process as Firefox itself, and thus the time measurements can be blocked when a web page contains long-running scripts. Here's an example ( http://stevesouders.com/cuzillion/?c0=bi1hfff1_0&c1=bb0hfff0_4&c2=bi1hfff1_0 ). This page contains two identical image requests that each take 1 second. In between the two image requests is an inline script block that takes 4 seconds to execute. Both Net Panel and HttpFox show that the first image request takes 4 seconds instead of 1 second. That is because the Firefox process is blocked from handling any events while the 4 second script executes, so the "http request done" event of the first image is missed.

This review is for a previous version of the add-on (0.8.4).