15 Highly Useful Firefox Web Developer Tools You Should Know About
If you are using Firefox as your main web browser while designing and developing websites and web applications, knowing all the available tools it offers will help you a lot during your development and testing sessions. Some of these tools you may need to use on a regular basis and some of these tools you may need to use less frequently, but having an idea what tools you have access to and how to open them may save you a lot of time in the long term.
How to Open Web Developer Tools in Firefox
The Web Developer tools can be accessed from the top menu bar of Firefox, which is not visible by default, so you will need to open it to see what tools you can use. To open the Firefox menu bar, you can press the Alt key on your keyboard, which will open the menu bar temporarily, or right click on the title bar at the top and select Menu Bar from the dropdown menu, which will keep it open permanently.
If you select Tools on the menu bar, and then bring the cursor over Web Developer option on the dropdown menu, you will see a list of available tools.
You can open each tool by clicking on its link or using its shortcut if you prefer to use Firefox keyboard shortcuts.
Now, let's see what web developer tools Firefox has to offer.
1. Toggle Tools
This tool opens and closes the bottom window with a number of developer tools such as Inspector, Console, Debugger, Style Editor, Performance and Network. Clicking this will open or close the bottom window.
The keyboard shortcut for Toggle Tools is Ctrl + Shift + I.
This tool opens the Inspector tab on the bottom developer tools window, where you can inspect any HTML elements on the web page, their HTML code and related CSS code. You can navigate within the tool via bringing your mouse cursor on any element on the page (it will be highlighted with transparent blue) or by using the source code viewer.
The keyboard shortcut for Inspector is Ctrl + Shift + C.
3. Web Console
This tool opens the Console tab on the bottom developer tools window, where you can access to highly important information such as network access logs, errors, warning, CSS errors, warning, JS errors, warnings, security errors, warnings and server errors, warnings. You can toggle any of the console elements to easily find the specific type of errors you are looking for.
The keyboard shortcut for Web Console is Ctrl + Shift + K.
This tools opens the Debugger tab where you can search and view scripts and their sources. Using this tool, you can prettify the scripts, pause them and use step over, step in and step out for relevant scripts.
The keyboard shortcut for Debugger is Ctrl + Shift + S.
5. Style Editor
Style Editor tool displays all the available style files on a web page. You can view and edit style files, change the CSS rules, create new style sheets or import them. If you are interested in custom styling websites, you can also try adding custom userstyles to Firefox.
The keyboard shortcut for Style Editor is Shift + F7.
Performance tool is used for recording performance of a web page and analyzing it. You can display the performance reports in waterfall, call tree or JS flame chart and see what events and actions are taking place on your page in the background.
The keyboard shortcut for Performance is Shift + F5.
Network tool doesn't display anything when you first open it. After opening it, simply reload the page to see all the resources used on the page, their domains, file types, sizes, the amount of time they required to download (related to your server bandwidth and Internet speed) and their HTTP status codes. This tool is extremely helpful while fixing bugs and identifying issues with your scripts.
The keyboard shortcut for Network is Ctrl + Shift + Q.
8. Developer Toolbar
This tool opens the developer toolbar at the bottom of the browser window, which has a command input line and a shortcut to open the developer tools window.
The keyboard shortcut for Developer Toolbar is Shift + F2.
This tool opens the Firefox web interactive development environment where you can create, preview and run apps, open or save projects. Using the WebIDE, you can install simulators to test your apps, connect to USB devices and remote computers.
The keyboard shortcut for WebIDE is Shift + F8.
10. Browser Console
This web developer tool opens the Browser Console with Network, Server, CSS and JS logs, which opens as a pop up window to provide you more space on the main window where you are previewing your website.
The keyboard shortcut for Browser Console is Ctrl + Shift + J.
11. Responsive Design Mode
Responsive Design Mode is a tool that you will most probably be frequently using if you are building mobile friendly, responsive websites and applications. It has a number of preset screen dimensions but it also allows you to create custom sized screens to preview your mobile websites. Also see this detailed tutorial about the Responsive Design Mode tool.
The keyboard shortcut for Responsive Design Mode is Ctrl + Shift + M.
Eyedropper is a simple tool to identify the color of a pixel on the browser screen. You can use it to quickly figure out what colors are used on a web page and get inspiration for your own designs.
Unfortunately, there is no keyboard shortcut for the eyedropper tool.
The keyboard shortcut for Scratchpad is Shift + F4.
14. Service Workers
This tool allows you to view and debug service workers, shared workers and other workers that are running on a web page.
Currently, there is no keyboard shortcut for the Service Workers tool.
15. Page Source
One of the most frequently used web developer tools, Page Source allows you to view the source code of web pages. Highly useful for spotting syntax errors and figuring out how things are done on other sites.
The keyboard shortcut for Page Source is Ctrl + U.
These are the web developer tools that come built-in with a fresh Firefox installation. You can get more tools as addons to Firefox, using the Get More Tools link at the bottom of the Web Developer tools list.
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