FireBug

Firebug is a free, cross-platform and open source add-on for the Mozilla Firefox web browser, designed to allow web developers and web designers to easily and quickly find flaws in the source code of their website(s).

With Firebug, you will be able to debug, edit and monitor HTML pages, CSS and JavaScript code, as well as DOM in real-time, live in any web page. It comprises of several components that help developers to stomp every bug on their websites, including a JavaScript debugger, an error console, a logger, and a JavaScript command line.

Getting started with Firebug

This Firefox add-on is easy to install, with a single click of a mouse, and requires no restart of the web browser. To open it and get started with web debugging, simply press the Firebug button from the main toolbar. The Firebug’s interface will open at the bottom of the window.

From there, you will be able to edit HTML code and view changes in real-time, but they won’t be applied to the website, of course. The add-on displays its components in tabs. The default tab is HTML, but you can easily choose to view CSS, JavaScript, DOM and .NET code, as well as cookies.

Firebug in interactive, which means that you will be able to click an element on the web page to inspect it. An error console is also implemented in the user interface, as well as quick access to the add-on’s settings.

The Firebug toolbar button

After installation, the add-on will automatically place a button on the main toolbar, allowing the user to quickly activate it, as well as to configure various essential settings, such as where to place the user interface (top, bottom, detached, left or right). The button also displays the total number of errors found on the current web page.

What is new in this release:

• Limit command history
• Console grouping should be listed in the options of the Console Panel
• Ctrl+Shift+C conflicts with Firefox DevTools' Inspector
• Absolute Xpath
• DebuggerLib.getInactiveDebuggeeGlobal can provide debuggers from a destroyed context
• getEventListeners includes the HTML panel mutation observer

What is new in version 1.13 Alpha 8:

• We introduced one nifty enhancement that allows displaying original CSS color values. There is a new option Colors As Authored that allows to display CSS color values as they were defined. This makes it easier to compare the styles interpreted by the browser with the ones inside the original CSS source file. While this new option is now the default, you still have the possibility to switch to hexadecimal, RGB or HSL formatting.

What is new in version 1.13 Alpha 7:

• Add auto-completion for HTML attributes
• Clicking and hovering the error badge should have different action than the toolbar button
• Jumping back to the property name while the property value editor is empty doesn't work
• console.log on generator object resumes it until it ends
• Auto-complete CSS styles within the HTML "style" attribute
• Auto-completion for SVG attributes
• Firebug inspector CSS is visible with '* { display: block; }'
• Fix search icon
• Cookie module activation is broken
• Broken styles for search elements
• Exceptions in editor.hide should be logged and ignored
• `include()` fails in error when having no alias
• Firebug bugs when updating the DOM every 29 ms or less
• console.log fails when called from JS injected by content script

What is new in version 1.13 Alpha 6:

• Number rep should show negative zero as "-0"
• Improve design of the search field and search options popup window
• Closure inspection is broken in Fx27
• Style panel right-click doesn't work when SVG tag is selected
• Toggles missing when "Show Enumerable Properties Only" is off
• Built-in array methods should be treated as DOM properties
• Remove all cookies shortcut doesn't have a tooltip
• Putting capital letters on attribute names duplicates them

What is new in version 1.13 Alpha 5:

• Fixes:
• Add auto-completion for selectors for elements in iframes
• Split firebug/firebug module into several modules and fix dependencies
• Only select the string without quotes when editing a string property
• Smartly recognize CSS selectors in the search field
• Use Debugger.makeGlobalObjectReference in getDebuggeeGlobal
• Selector auto-completion doesn't filter selectors that come after combinators
• Exceptions in endEditing should be logged and ignored
• Be a bit more restrictive with selector completions
• HTML panel - search: Sometimes the search is not highlighted

What is new in version 1.12.4:

• This version introduces a workaround that solves Firefox tab switching and Firebug activation problem (see a platform bug). As a temporary measure, Firebug no longer pauses the debugger when switching tabs. This avoids long tab switching times (see issue 6086 for more details).
• The entire problem will be properly fixed in the next major Firebug version that will be based on the new JavaScript Debugger API in Firefox.

What is new in version 1.12 Alpha 7:

• Group Console Messages (issue 4979)
• Create selector groups for Elements side panel (issue 5955)
• Issue 6447: Improve display of timings in net request infotip (issue 6447)

What is new in version 1.10.5:

• Location list in the Script panel can be filtered (Issue 5963)
• Title in Firebug detached window is correct (related to Issue 5883)
• Firebug can be opened in popup windows (Issue 5949)
• First-run page is not opened till Firefox restart when Firebug is updated (Issue 5888)
• Firebug properly shows scripts coming from iframes (Issue 5978)

What is new in version 1.10.4:

• Issue 4929: Update list of inherited properties
• Issue 5783: Display of IPv6 addresses with port number is incorrect
• Issue 5859: Delete "element.style" is broken
• Issue 5883: Error "topWindow.exportFirebug is not a function" while Firebug is detached
• Issue 5946: Firebug breaks Firefox UI when disabled
• Issue 5945: Show source link for CSS errors
• Issue 5908: Link to open the complete xhr response in a new Firefox tab does not work
• Issue 5744: Radio button deselects when Firebug is open (situational)
• Issue 5905: inspector blinks

Requirements:

• Mozilla Firefox