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Firebug & Chromebug

EU MozCamp, Prague, October 2009
Jan Odvárko

Firebug Developers

  • John J. Barton
  • Jan Odvarko
  • Rob Campbell
  • Kevin Decker
  • Mike Radcliffe
  • Hernan Rodriguez Colmeiro
  • Curtis Bartley
  • Mike Collins
  • Hans Hillen
  • Contributors, Localizers, ...

Firebug Status

Console panel

  • Persistent across page reloads (history of all logs)
  • Show Network Errors (Use Console -> Show Network Errors option

HTML Panel

  • Debugging HTML
    • Break on Mutation
    • Break on Attribute Change
    • Break on Child Addition or Removal
    • Break on Element Removal
  • CSS Selector Search
    (maybe not part of 1.5)

Next: Breakpoint Bar

Script Panel

  • API for source code decorations
    • Colorize Source Code (FireRainbow extension)
    • Decompile source code (unminified)
  • Performance (scripts on pageas are bigger and bigger)

DOM panel

  • Break On Property Change

Net panel - Visualize HTTP

  • JSON Explorer
  • XML Explorer
  • Next: WDDX Explorer (Web Distributed Data eXchange)?
  • Better UI for posted data
    • application/x-www-form-urlencoded
    • multipart/form-data
    • Next: multipart/x-mixed-replace
  • Columns Visibility Customization
  • Next: Sorting, Resizing

Net panel - Debugging HTTP

  • Break On XHR
  • Conditional Breakpoints
    • URL parameter value
      'param-name' == 1
    • Post body value
  • Next: Peristent content across reloads

Break On... Next steps

  • Further Polymorphic Breakpoints
  • APIs for extensions
    • Break On CSS
    • Break On Cookies (Firecookie extension
    • ...
  • Support Conditions for all kinds of Breakpoints
    • Conditional Break on Errors
    • ...

Export HTTP Logs

HTTP Archive (HAR)

Event Listeners

Save Changes

Future Plans

  • Better support for extension ecosystem (testing, doc, bundles)
  • Net panel persistence (history of request)
  • Better & generic Search UI for all panels.
  • Memory panel, inspection, GC events, closure size BUG #515946
  • Break on CSS, Break on Cookies, Break On...
  • Storage panel (local storage, session storage, globalStorage, client side database)
  • Custom Command Line APIs


  • Author: John J. Barton
  • Debugging a debugger
  • Aka Firebug for Firefox Extensions
  • Based on Firebug source base

Links & Questions