Firebug's Net panel offers an option called Show BFCache Responses that allows tracking also responses coming from BFCache. But what the heck is this cache for?
Read this post to understand how this cache is different from the standard browser cache and why Firebug supports it.
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Updated: how to use this feature from the command line
Have you ever placed console.log into a JS function just to figure out whether the function has been executed? Did you also happen to make a syntax error when doing that code modification? 
Then you could be interested in Firebug feature that allows to log function calls without changing the code!
This feature is ready behind a Log Calls To ... menu item that is available if you right click on a function link (e.g. in the DOM panel).
See all Firebug tips
Updated: how to use this feature from the command line
This Firebug feature is called simply Log Events and allows developers to log DOM events into the Console panel.
All you need to do is right click on an element in the HTML panel, pick Log Events from the context menu and switch to the Console panel to see the logs in action.
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Firebug is mainly a debugger and being able to stop Javascript execution on a breakpoint is obviously one of its essential features.
Also, ability to break on a breakpoint only if certain condition is true is useful feature and so, check out this post if you are interested how to properly create a conditional breakpoint in Firebug.
This post covers three types of conditional breakpoints.
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Firebug is a tool for web developers and its features like JavaScript debugging and HTML/CSS inspection are well known, but there are also many little features users often don't know and so, they deserve more publicity.
One set of such features is related to XML and I'd like to describe them in this post. So, let's see what Firebug offers to developers who deal with XML!
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Break on HTML mutation feature has been introduced in an article Dynamic and Graphical Web Page Breakpoints submitted to WWW 2010.
This feature is great for exploring and learning an existing code that is dealing with HTML/UI. It allows the Firebug user to break JavaScript execution when various HTML mutation events happen and see the line of code that caused that event.
There are three types of mutation events.
Let's go over three simple examples that explain how to use the feature and how it can be useful to web developers. Each example is available live on this page and so, you can just open Firebug UI (or install Firebug) and try it out immediately.
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Firebug 1.10 has been released today and one of the new features introduced in this version is called Trace Styles.
This feature allows tracing all places which affected specific CSS property, whether explicitly or by inheritance. The list also shows which property is actually applied.
This feature is integrated into the Computed side panel (available within the HTML panel) where every CSS property is expandable.
Of course, you need Firebug 1.10+ to try out this feature.
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I have been recently working on an extension (code name HTTP Monitor) that can be used to intercept HTTP traffic of a browser tab. The extension is based on Firebug's Net panel and is on its way to be embedded in Firefox by default.
This post explains how to use HTTP monitor to intercept HTTP traffic on mobile with Fennec (Firefox for Android) installed.
We have decided to extend cooperation between Firebug and Firefox dev-tools teams (I am a member of both) and so, discussed this topic about four weeks ago at our meeting in London.
We agreed that we want to have an effective and synchronized strategy when working on in-browser developer tools. One pillar of the plan is sharing APIs, components, modules, code maintenance, etc. to avoid duplicate development effort.
The first step is sharing an independent HTTP tracking component that is based on Firebug's Net panel and can be shared among all tools that want to intercept an analyze HTTP traffic. Firebug and (built-in tools in) Firefox will be its first clients.
So take a look at what we have managed to implement and demonstrate for our Toronto meeting last week.
I had a chance to attend MozCamp CZ 2012 that happened in Brno last Saturday. It was one day meeting filled with sessions and discussions about Mozilla related stuff.
I had also great opportunity to lead a session about Firebug Tips & Tricks where I also mentioned some useful Firebug extensions. Check out my slides (en-US), but I am not sure how useful they are without me talking
We discussed many interesting topics and here is a brief summary of what stuck in my memory.
If it sounds interesting to you, you should join us the next time! Follow Mozilla.cz to know when the next MozCamp CZ happens.
Photos provided by Jan Horák (Red Hat)
