Firebug is slowing down my Firefox

Posted by james on April 22, 2008

I use the Firebug extension for Firefox. It's an incredible help when debugging javascript, as it can tell you exactly where an error occurred, what the current DOM is (not the static code), etc. It can be selectively enabled or disabled per site, so I enable it only for localhost and my dev server. However, I've noticed that firefox has been really slow lately when I have a lot of tabs open. Specifically, when I go to create a new tab (Control+T), there is a 1-2 second delay before it opens. It gets really annoying, since I open tabs all the time during browsing.

I also knew that when I would run Firefox with a clean profile, it would be much faster. So I disabled all extensions, and then repeatedly loaded 10 heavy sites and then opened a new tab. Everything was fine until I enabled firebug; immediately, the delay is back. So even though firebug is only "enabled" for certain servers, it looks like it's slowing down firefox for all sites, at least on my computer. So I'm going to have to enable firebug whenever I'm developing, and then disable it when I'm not. It's slightly inconvenient, but I'm just too glad to get a snappy browser back.

There could also be some interaction between different extensions that is causing the problem. I didn't test for that, however.