Firebug can slow Firefox to a crawl

Firebug is a great tool for analyzing and debugging HTML, CSS, JavaScript, and more. I love it. But I also hate it. As of Version 1.3.2, it stores information about almost every resource downloaded as you browse the web, regardless of whether or not you have Firebug turned on. For someone like me that averages 10 open tabs at a time and well over a thousand page views per day, this eventually causes Firefox to take more and more memory and eventually slow to crawl. One solution: restart Firefox. I find this to be a real pain, so until they make some changes that make “off” really “off” (rumored to be part of 1.4), the problem is completely solved by disabling Firebug entirely. This means I have to enable it and restart Firefox to make use of it, but that is much less frequent than my restarts due to memory bloat.

To disable Firebug on a Mac, go to Tools / Add-ons. Under Extensions you can disable Firebug.

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7 Responses to “Firebug can slow Firefox to a crawl”

  1. johnjbarton Says:

    By default Firebug records nothing; by default Firebug is off for all sites. So if you think Firebug is taking lots of memory, you have some option set. You can ask for help in the newsgroup:

  2. Josh Freedman Says:

    I’ve been tinkering a lot more with various Firebug settings that can affect memory usage. Here are some suggestions.

    First, disable Firebug’s Console, Script, and Net panes. Do this by clicking on the down arrow next to each tab’s name and select “Disabled.” This doesn’t prevent it from collecting data however. Firebug may still be turned on for specific domains, and this is easy to do without realizing it or remembering it later.

    To turn off site-specific capabilities, click on the arrow on each of the aforementioned tabs again and select “Sites…” You can now remove specific web sites. Note that you’ll have to repeat this for each of the three panes — Console, Script, and Net — individually.

    Last of all, John J Barton recommends setting all options to their default values. These options can be found by entering “about:config” (without the quotes) into Firefox’s address bar, then typing “extensions.firebug” into the filter text box. For any preference whose status is not “default”, right click on it and select “Reset.”

  3. Bobo Jones Says:

    Revert to Firebug 1.2. Still compatible with Firefox 3, and much faster. The last few versions of Firebug left me wondering what had actually changed. Nothing that mattered to me, save for some performance killing stuff.

    Yet another case of newer not being better. Old Versions FTW

  4. ave Says:

    I really love Firebug, but sometimes it gives me more problems than it solves. It was so fast and good enough with the earliest versions. Too bad, I had to upgrade because of incompatibility with the browser.

  5. Jeff Says:

    This is ridiculous. I don’t care what the developers of Firebug *claim* about how Firebug behaves when viewing sites for which it’s supposedly “off”, the fact is, it still slows Firefox to a crawl. When a page loads, Firefox just freezes up for as much as 20 seconds. And the release that came out last week has made it even worse, at times causing Firefox to crash completely. I do a lot of development that requires I keep Firebug running; I can’t just switch to a different profile that has it uninstalled. But facebook + firebug is horrid. Basically I now use two browsers at any given time — both Firefox for my dev work, and Google Chrome for everything else.

    Now I know Firebug is free, and it’s the only tool that does what it does. So I guess we’re kind of stuck here…

  6. John Upday Says:

    Ok, this thread is over one year old and the original author is probably not interested anymore, but I found it after I googled the same problem so I hope I can help others with the same problem.

    I had the same issue and I didnt tweak Firebug at all (newly installed). For me it started to get slow after I activated the console and the script tabs and debugged some Javascript code. The page I was debugging was not responding for a few seconds every time I tried to do something and it took ages to switch between tabs in the browser. However, after inactivating the console-tab in Firebug everything went back to normal.

    Try inactivating the console tab in Firebug, that seems to be the cause of the problem (at least it was for me).

    Hope that helps.

  7. Omar Says:

    It does slow it down considerable, so until it doesn’t, I’ll just disable it, at least when doing doing Web duties.