Questions tagged [firefox-developer-tools]

The Firefox Developer Tools are the built-in development tools in Mozilla Firefox.

This tag is reserved for the built-in development tools in Mozilla Firefox. For any other third party development tools, use the appropriate tag, for example .

You can use the developer tools to examine and edit HTML and CSS, to debug JavaScript, and to run JavaScript in the page. You can use them to see network requests that your browser makes as well as any JavaScript and CSS warnings and errors that it encounters when loading a page. You can use them to debug performance problems with your site.

You can use the developer tools to debug code running Firefox for Android, and soon, Firefox OS. We've also provided tools that target mobile development: the Responsive Design View is a quick way to see how a site will look on a small screen, and the Firefox OS Simulator lets you run and debug a Firefox OS app on the desktop without needing to use a real Firefox OS device.

Firefox add-ons can access the debugger API, so you can build your own developer tools that extend and enhance the built-in tools. With the remote debugging protocol you can implement your own debugging clients and servers, enabling you to debug websites using your own tools or to debug different targets using the Firefox tools.

You can learn more at the official Firefox Developer Tools site: https://developer.mozilla.org/en-US/docs/Tools

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How to view log of network requests across tabs in Firefox?

Within Firefox, I would like to see all network requests being made by Firefox. Using Firefox developer tools works great for this. Just open the developer tools, click on Network, and there you go. The problem happens when a site opens a link in a…
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1 answer

How to make Chrome show beginning and end of long URLs in the URL bar

I've been trying to find a Chrome extension that would show the beginning (www.domain.com/...) and ending (someFileorPage.html) part of a URL, in the omni-bar, truncating the middle part if the URL's too long to fit. The beginning and ending parts…
Qasim
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5 answers

Firefox: change/disable default keyboard shortcut configuration

I have installed the Keyconfig add-on and configured it to toggle Offline Mode on Firefox, whenever I press Ctrl + Shift + O. It worked fine on previous versions of Firefox (before version 28.0). However, now, when I have the Developer Tools pane…
Janaka Bandara
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How do I modify a variable at a breakpoint in Firefox Developer Edition?

I would like to be able to edit a variable after setting (and hitting) a breakpoint, in either Firefox or Firefox Developer Edition. It seems that it used to have this feature, but it was removed when the debugger was reimplemented. There used to be…
Aster
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Loading a URL in the current tab through the Firefox “Browser Console” (or command-line)

For debugging purposes, I need to automatically load a large number of URLs (successively) in a given Firefox tab. More precisely, my goal is to load URL1, URL2, etc., as if the user had typed these URLs in the URL bar and typed return, always in…
Gro-Tsen
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1 answer

Firefox devtools: how to hide console from other dev tabs?

When I open my Firefox 55 devtools (F12), the Console shows up under every tab. Here it's taking up the bottom 40% of the Network Monitor tab: This can be useful if I want to see new console messages as they appear, but it's annoying when I don't…
BeetleJuice
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How to turn on Firefox's Responsive Design Mode's touch simulator?

I want to use Firefox for mobile development. And I would like to turn on Firefox's responsive design's touch simulator. While I'm in device mode in Chrome, the browser shows a gray circle as mouse cursor and I can drag (slide) my page: But in…
Java Jedi
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Firefox: purge all data (cache, cookies, local storage, etc) for a specific website

Chrome has this handy tool: Lets you purge all kinds of storage for a specific website without ruining your experience for all other websites. How do I do the same in Firefox?
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How do I turn off groupLogMessages in Firefox console, not Firebug?

I know how to do this in Firbug, but want to disable the grouping (red circle with a number in it) in the regular console. I've searched inside about:config, but couldn't find it. Is this possible?
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1 answer

Firefox - re-attach Developer Tools to main window

Since it is possible to "pull out" the Developer Tools, so they appear as an own window, I would like to know if there is a way to restore the original form of the Firefox Developer Tools, so it shows below the website in the active Firefox window…
who.knows
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1 answer

How to turn off accessibility in Firefox?

I was turned on accessibility service on developer tool but I cannot turn if off. The turn off button said Accessibility service cannot be turned off. It is used outside Developer Tools. From this link said that Once the panel content loads,…
vee
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1 answer

Cannot remove breakpoints in Firefox debugger

I added some breakpoints in Firefox debugger and when I removed them, they just disappear in the Breakpoints list.Then, when I load the page, it still pauses at the breakpoints. If I close the Developer Tools window and open it again, the…
wh201906
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How do I search with XPath in Firefox Quantum 65?

I used to use FirePath and FireBug for XPath support in Firefox a long time ago, but those tools haven't worked with Firefox for some time. I was disappointed but found that I could still use the find feature in the inspector developer tool to look…
nikodaemus
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How to change the width of the columns in Firefox’s developer tools’ network tab

In Chrome, I can customize the width of the columns in its developer tools’ network tab: In Firefox, I can’t figure out how to do the same thing: Is it possible?
Jackson
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Firefox Developer Tools failed to inspect variables on hover over

I have FireFox Quantum 57.0.2 (64 bits) and Windows 8.1. It was working fine till now, but suddenly I can't get pop up value on hover over variables. This and other issues come up in all pages regardless of the code. I have tried the…
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