The Toolbox provides a single home for most of the developer tools that are built into Firefox. You can open it by selecting "Toggle Tools" from the Web Developer menu (under "Tools" on OS X and Linux, or "Firefox" on Windows), or by activating any tool hosted in it (for example, the JavaScript Debugger or the Page Inspector).
By default, the window appears docked to the bottom side of the Firefox window, but you can detach it if you like. This is what it looks like when it's docked:
The window itself is split into two parts: a toolbar along the top, and a main pane underneath:
Toolbar
The toolbar contains controls to activate a particular tool, to dock/float the window, and to close the window:
On the far left is a row of buttons to:
- close the window
- toggle the window between attached to the bottom of the browser window, and attached to the side of the browser window
- toggle the window between standalone and attached to the browser window
- access developer tool settings
Then there is an array of labeled buttons which enables you to switch between the different tools hosted by the Toolbox. The array may include the following tools:
Note that not all the hosted tools are always listed here: only the tools actually available in this context are shown (for example, not all tools support remote debugging yet, so if the debugging target is not the Firefox instance that launched the window, not all the hosted tools will be shown).
Next there's "Select element": this button was moved into the Toolbox toolbar from the Page Inspector in Firefox 29. If you click this button, then as you move around the web page you'll see a dotted border around each element. Click the element, and the Page Inspector will open with that element selected.
Next there's a button to activate and deactivate the split console. This enables you to use the web console without switching away from the tool you currently have active. This button's only available from Firefox 28 onwards.
Finally, the icons at the far right enable you to launch various tools whose user interfaces are not hosted by the Toolbox:
Settings
Clicking the "Settings" button gives you access to settings for the Toolbox itself and for the tools it hosts:
Default Firefox Developer Tools
This group of checkboxes determines which tools are enabled in the toolbox. New tools are often included in Firefox but not enabled by default.
Choose DevTools theme
This enables you to switch between a light and a dark theme:
Inspector
This setting is available from Firefox 27 onwards
Default color unit: a setting to control how colors are represented in the inspected: Hex, HSL(A), RGB(A), and by name.
Web Console
Enable persistent logs: a setting to control whether or not the console clears the output when you navigate to a new page.
This setting is available from Firefox 28 onwards
Enable timestamps: controls whether the Web Console displays timestamps. From Firefox 28 the Web Console defaults to hiding timestamps.
Style Editor
These settings are available from Firefox 29 onwards
Show original sources: when a CSS preprocessor supporting source maps is used, this enables the Style Editor to display the original, preprocessor, sources rather than the generated CSS. Learn more about Style Editor support for CSS source maps. With this setting checked, the Page Inspector Rules view will also provide links to the original sources.
Autocomplete CSS: enable the Style Editor to offer autocomplete suggestions.
JavaScript Profiler
Show Gecko platform data: a setting to control whether or not profiles should include Gecko platform symbols.
Advanced settings
- Disable cache: disable the browser cache to simulate first-load performance
- Disable JavaScript: reload the current tab with JavaScript disabled
- Enable chrome debugging: enable you to use developer tools in the context of the browser itself, and not only web content
- Enable remote debugging: enable the developer tools to debug remote Firefox instances
Main Pane
The content of the main pane in the window is entirely controlled by, and specific to, the hosted tool currently selected.