Firefox Developer Tools ideas

Welcome to the feedback channel for Firefox Developer Tools. This is a place for constructive feedback around the tools with ideas and feature suggestions. It is not a support forum or place to report bugs. For support, please go to the #devtools channel on Mozilla IRC or the firefox-developer-tools tag on Stack Overflow, and for reporting bugs, go to Bugzilla.

The documentation on how the Developer Tools work is available on MDN.

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  1. A JS editor

    Suppose we could edit JS just as we can edit CSS with the CSS editor. So we can change things on the fly and get instant feedback without having to reload the page. Right now the most I can do with regards to JS code is... debug it, which is a bit limiting.

    It'd be awesome if I could edit the code of a function and have it automatically reevaluated and stuff. Not sure if this is even possible at all but hey this is an idea.

    354 votes
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      12 comments  ·  Flag idea as inappropriate…  ·  Admin →
    • Inspect websocket connections

      It will very useful for who works with websockets inspect the traffic and connections.

      278 votes
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        6 comments  ·  Flag idea as inappropriate…  ·  Admin →
      • Memory monitoring

        I want to be able to monitor memory usage in my mobile web app. I want my mobile ap to use as little memory as possible.

        247 votes
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          started  ·  13 comments  ·  Flag idea as inappropriate…  ·  Admin →
        • Can you please add user agent switcher in tool?

          Add device, screen size and user agent in under user switcher control.

          207 votes
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            4 comments  ·  Flag idea as inappropriate…  ·  Admin →
          • Give me a way to *fully* emulate the mobile browser in FF desktop

            Not just emulating dimensions for responsive. Browser should override media queries, lie about other feature detects, etc, so my mobile app ACTUALLY WORKS like it's on mobile.

            178 votes
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              4 comments  ·  Flag idea as inappropriate…  ·  Admin →
            • CSS Animation Editor

              CSS frame-by-frame animation editor. I believe someone on devtools started this project (might have been Paul Rouget?) and I would love to see it resurrected.

              170 votes
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                started  ·  6 comments  ·  Flag idea as inappropriate…  ·  Admin →
              • easier cookie deletion

                Deleting a cookie right now is quite cumbersome. You have to bring up the developer toolbar, then use the cookie list + cookie delete commands.

                It would be a lot easier if the cookies could be deleted directly from the tools. e.g in the network tab, where cookies are listed.

                142 votes
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                  5 comments  ·  Flag idea as inappropriate…  ·  Admin →
                • Grey out non-applied fonts

                  Consider this example CSS rule:

                  body, td, th, input, select, option, optgroup, .text_input {
                  font-family: "Open Sans","Helvetica Neue",Arial,Helvetica,sans-serif;
                  }

                  Only one of these fonts is going to be applied on the page, depending on what is available on the system.

                  It would be nice if the devtools' Rules view would grey out all the fonts that are not actually applied, so as to let the user know which one got applied in the end.

                  related bug: https://bugzilla.mozilla.org/show_bug.cgi?id=994559

                  128 votes
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                    planned  ·  0 comments  ·  Flag idea as inappropriate…  ·  Admin →
                  • Recalculate JS line numbers after pretty print

                    Whenever there is any kind of console notification (log, warn, error, etc) it prints the line number, and clicking that takes you to that line in the debugger. However, if your code is minified that number is invariably 1 or 2. There is already the option to pretty print minified code, but it would be nice if after prettifying, you could then jump to the actual line number that triggered the console alert.

                    Chrome currently supports this.

                    Thanks for all the awesome work everyone!

                    128 votes
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                      3 comments  ·  Flag idea as inappropriate…  ·  Admin →
                    • 103 votes
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                        planned  ·  0 comments  ·  Flag idea as inappropriate…  ·  Admin →
                      • Security Tab - to show TLS/SSL, CSP, SRI, etc features

                        Add a "Security" tab to highlight features that the browser provides.

                        e.g. most developers have no idea what a CSP (Content Security Policy) header is... and even if implemented, the only way to view it is though the network headers (not easy to read).

                        This new tab can help list features, and make suggestions on how to make improvements (e.g. adding HSTS, or HPKP, or X-XSS-Protection, or X-Frame-Options headers).

                        I've started making a mockup on GitHub, so you can click around to see what could be included (I bet there is at least one thing on there you didn't know…

                        95 votes
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                          5 comments  ·  Flag idea as inappropriate…  ·  Admin →
                        • Support live editing with any external editor

                          The architecutre of fb-flo is very nice: http://facebook.github.io/fb-flo/

                          It sounds like it needs some deep JavaScript VM foo to do hot code reloading.

                          Maybe a Fx Addon for Facebook Flo support?

                          Maybe a from scratch way to support any external editor with any codebase?

                          81 votes
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                            3 comments  ·  Flag idea as inappropriate…  ·  Admin →
                          • Better output for objects and arrays

                            The way it is nowadays, we can only see one object at time!
                            It would be much better if we could, for example, expand or compact multiple objects ... this way, we could even compare objects or arrays.

                            79 votes
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                              3 comments  ·  Flag idea as inappropriate…  ·  Admin →
                            • show a diff of style changes manually entered in the styles pane

                              When you make style changes, it would be awesome to have an option to show all your changes across the page together, for ease of extracting experimental changes.

                              E.g. I've made changes to a bunch of stuff, trying out a new style, and now I have to remember the changes I made, or at least the dom nodes so I can navigate to them and copy them out.

                              79 votes
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                                1 comment  ·  Flag idea as inappropriate…  ·  Admin →
                              • Make collapsing margins visible and show from which element they come from

                                When inspecting HTML elements, CSS margins which collapsed should be highlighted with a new color. It also would be nice if it was possible to show some information about the elements involved and which the margin of which element is visible.

                                67 votes
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                                  2 comments  ·  Flag idea as inappropriate…  ·  Admin →
                                • Connexion throttling

                                  It's been a while since I was looking for such a feature, and Chrome added it this summer.
                                  As a web developer, I would love a native tool to reduce bandwidth in order to simulate a slow mobile (or ADSL) connexion to improve the user experience in those cases.

                                  67 votes
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                                    1 comment  ·  Flag idea as inappropriate…  ·  Admin →
                                  • Inspect accessibility information

                                    Show computed(implicit)/declared(explicit) ARIA information for accessibility purposes. In particular being able to jump to nodes related to the selected Node would be handy.

                                    64 votes
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                                      1 comment  ·  Flag idea as inappropriate…  ·  Admin →
                                    • Ability to resize columns in network pane

                                      Currently the columns in the network pane are fixed width. Sometimes I want quickly look at a number of requests which all go to the same domain and have long urls (the part I want to see is at the end).

                                      63 votes
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                                        2 comments  ·  Flag idea as inappropriate…  ·  Admin →
                                      • Live html editor like in firebug

                                        Hello there!
                                        The only think that keep me from switching to firefox devtools completely is the luck of live html editing.

                                        In firebug when you inspect the Dom tree there's an edit button on the left top corner that lets you edit the html I'm real time. This is very very helpful when you build or edit html frameworks.

                                        Right now you can right click and edit the html but to see the changes you have to click outside of the box.

                                        Hope you understand! Keep up the good work :)

                                        60 votes
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                                          0 comments  ·  Flag idea as inappropriate…  ·  Admin →
                                        • Persistent multiline command editor (like Firebug)

                                          Firebug has the ability to switch between the Command Line (one-off commands) and the Command Editor, which is multiline, syntax-highlighted, and most importantly *persistent* (Cmd/Ctrl+Enter to run the code, then you can play around with it). This is mostly what's keeping me from switching from Firebug to Developer Tools.

                                          (Also please make sure that it runs in the same context as the console; Chrome has a kind of similar feature called Snippets, but they don't run in the breakpoint context when debugging, making them much less useful).

                                          52 votes
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                                            4 comments  ·  Flag idea as inappropriate…  ·  Admin →
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