Turning off the ‘friendly HTTP error messages’ in Firefox

By accident I stumbled upon this Firefox somewhat equivalent of IE’s ‘Show friendly HTTP error messages’ option. Any webdeveloper should have this turned off by default. How else will you know what the problem is? So here’s how to do it:

1. Open up a new tab (CTRL+T) or window (CTRL+N).
2. Type in de addressbar: about:config.
3. In the filterbar type: error and press enter.
4. Now set the value of the ‘browser.xul.error_pages.enabled‘ to ‘true‘. Double clicking will do.
5. Restart Firefox.

Now you’ll get extended warnings instead of the simple warning dialogs when, for example, you accidentaly link to a non-existant domain. Or, like me, the dreaded ‘The document contains no data’.

If you don’t know where to find this in IE: ‘Tools’ > ‘Internet Options…’ > ‘Advanced’-tab > Near the end of the ‘Browsing’-section. > Uncheck.

This entry was posted on Wednesday, June 22nd, 2005 at 11:31 pm and is filed under Browsers, Design, Development, Firefox, General, Internet, Internet Explorer, Intranet, Webdesign, WebDev. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

Previous article: Google Maps expands to Europe, needs to learn more… Next article: To Watch: Microsoft to Add Ordered List support in RSS?

---

9 Responses to “Turning off the ‘friendly HTTP error messages’ in Firefox”

1. The Code Couch - urning off friendly HTTP error messages in Firefox Says:
   December 27th, 2005 at 5:36 pm

   [...] http://www.thinklemon.com/weblog/2005/06/22/turning-off-the-friendly-http-error-messages-in-firefox/ [...]

2. Code Couch » Turning off friendly HTTP error messages in Firefox Says:
   May 16th, 2006 at 11:39 pm

   [...] http://www.thinklemon.com/weblog/2005/06/22/turning-off-the-friendly-http-error-messages-in-firefox/ [...]

3. s Says:
   August 24th, 2006 at 5:35 pm

   I tried this in Firefox and it has always been set to true, which is the default. However, I still get the friendly error messages.

   On another note, if I enter a URL (i.e spike), (which runs off to my localhost spike proxy), and the proxy is down, instaed it looks up on Google and sends the request to spiketv.com (or net), which is rather sad.

   Anyone know how to solve this one as well?

   Cheers,s

4. Caspar Says:
   August 24th, 2006 at 11:26 pm

   This setting was only valid in the Fx1.0 days. When all you got was an alert box stating Firefox couldn’t do something, instead of telling exactly what went wrong. Since 1.5 it’s the other way around. Now you’ll get an error page instead of a dialog box. (Setting it to false still reverts back to the dialog.)

   If Firefox cannot resolve the address (spike) it’ll do an ‘Im feeling lucky’ on Google. That’s why you’ll end up on ‘spiketv’. To tell Firefox to look on your localhost no matter what, you’ll need to do some rerouting on your system (I assume). On Windows you’ll need to alter the HOSTS-file and tell the OS ‘spike’ is ’127.0.0.1:(port)’. But look that up as it’s too long a story to post here.

5. Caspar Says:
   August 24th, 2006 at 11:45 pm

   On a sidenote: Roachfiend.com has a post on hacking Firefox’ error pages. But that’s probably not for the faint of heart.

6. Joe Green Says:
   October 20th, 2009 at 10:23 am

   I applied the change to turn off the “friendly” messages (what could be more friendly than 404 or 500?!) and closed FF but when I tried to restart it, I was told it was already running and I had to reboot. I also still get the messages this change was meant to disable. Sigh.

7. Quinn Says:
   October 4th, 2011 at 6:35 pm

   s says: I tried this in Firefox and it has always been set to true, which is the default. However, I still get the friendly error messages.

   Yup. Me too.

8. Jayden Lawson Says:
   April 11th, 2012 at 5:58 am

   ummm… I think he’s got this a little confused.

   It should be set to false.

9. Jayden Lawson Says:
   April 11th, 2012 at 5:58 am

   Also – just restart your browser after setting it to false

Reply to the article or a commenter

Comment on this article

Name (required)

Mail (will not be published) (required)

Website

Please note that your comment may be withheld from immediate publication. Keep your comment on-topic/on-commenter and your comment will be published ASAP. (Off-topic comments will be deleted at the moderator's discretion. Please us the contact form if you feel your comment has been deleted unduely.)