Diễn đàn hỗ trợ Firefox

Firefox says I need a video codec to play a video (that is aparently somewhere on the page). It does NOT tell me what video, what video format, or what codec I need. How do I find out what codec I need?

Firefox version: 101.0 (64 bit) OS: Fedora 36

so firefox I am logged out, you can tell where it say "save and sync - sign in". but even though I am not signed in, my passwords and addons are still showing up.

how to fix this

thank you!!

Hi,

I use Mendeley Web Extension to pull articles and other things from Firefox directly into my Mendeley library. I will usually rapidly read through the PDF file online before deciding to add it or not. For some unknown reason, Firefox blocks the use of Mendeley on PDF file, for security reasons, and I can no longer add them to my library. Most references are only available as PDF files making the add-on completely useless. Is there a security feature that I can disable to be able to use the extension again?

Kind regards,

Mathias

I've been using Firefox almost exclusively for years now, and it's always worked flawlessly - until recently! Now, when I log into my GitHub account, I can no longer edit and commit my changes.

When I click on the "pencil" on a rendered page, I am taken to the "edit page" where I can make my changes (in markdown), preview those changes (rendered in markdown), and then commit those changes. Beginning very recently (within the past few days), the preview tab is no longer functional, and I can no longer commit my changes to the file.

I've verified that GitHub has not changed their interface by logging in from my Chrome browser, and following the exact same procedure used in Firefox everything works as it always has.

I recently upgraded from ver 99 to 100, and now to 101.0.1. I recall clicking a pop-up immediately after the 99-100 upgrade that had something to do with cookies... sorry, I know that's lame, but it's all I can recall now. In any case, I am certain this happened recently.

Please help... I have to use Chrome for a couple of things already (my brokerage account at Vanguard for example), but I despise Google, and want to limit their spying.

Thanks,

Hi, I have this problem that is driving me crazy, I know it is not an issue with firefox but I really appreciate any help.

The problem is that there is a grey html code in inspector when rendering the html page, the grey code is not exist in my original file but that grey code I had already deleted it after using it a while, but it is still appears as grey code in inspector and this made me some issues in jquery.

So how can i get rid of it ?

Thanks

For some reason, whenever I load a pdf from within Firefox, I get a new tab with the regular toolbar displayed on top of pdf files, but the document itself is completely blank (see attached screenshot). This issue just started today and I assume it was a result of an update, since I don't recall making any changes to my settings (I'm using Firefox 101.0.1 on Ubuntu 20.04).

I've tried opening multiple files from a variety of sites with the same result. All of them open fine using my system's pdf viewer, as well as from within Chromium. I've tried disabling my plugins, putting Firefox into safe mode and resetting all the handlers, to no avail. Any help would be much appreciated.

I used a siteblocker and i tried blocking about:addons, wouldn't allow it so someone tell me how. im literally trying to prevent myself from removing extension i literally jumped from one browser to another just to make this shit possible please.

I'm using 64-bit Linux Mint 20.3 LTS, and the latest version of Firefox from the repositories (101). Suddenly, for no reason I know, my default profile has started crashing immediately on trying to run Firefox. A small window comes up with the error message

XML Parsing Error: not well-formed Location: chrome://browser/content/browser.xhtml

     <button when-cofnection}"secure-cert-user-overridden"="" <="" pre="">
and then a line of ------^  where the ^ indicates between the t and the i of cofnection
Yes, I emphasise that I HAVE copied the error message carefully, including the mismatched bracket pair and the cofnection rather than (I assume) connection
I've managed to get a working version of Firefox by creating a new profile and using that (as in for posting this request for help), and I do have a recent backup of my bookmarks, but it will be a royal PITA if all my logins and passwords have disappeared. I don't want to go any further than this without some guidance, as all the messages I've found detailing how to fix this seem to make the assumption that I'm running Windows. 
Can anybody help, please?
</button>

Instacart webpage suddenly will not display/open on Firefox but can display fine on Chrome. Instacart App on mobile phone works fine, just won't open in Firefox. Any suggestions other than using Chrome? Firefox version 101.0.1 Windows 10. Was working fine until latest update installed this morning.

Why are google sites (Youtube, Gmail and Search) getting disconnected when all other sites are still connected to the Net? This has been happening since November 2021.

When that happens I close the FF and then immediately open it. Now the google sites work properly.

Never had that problem with other sites.....never!

Why the hell is this happening? Is FF responsible or Google?

So what is the solution?

Hello, I experience a XUL Runner error message after attempting to update Firefox and in following the guidance to rectify the error deleted the Firefox folder including the bookmarks. Is there anyway of recovering the bookmarks (maybe with a third party program) or are they lost forever? Thank you.

Lighter fonts (from multiple families, and on multiple websites) are rendered so poorly they are barely legible.

I already tried disabled performance settings, and turning off ClearType in Windows (it barely had any effect)

How do we fix this?

Unable to complete backup of firefox profile because of over-length file names in storage sub-directory. Is is ok to simply delete one or more file names which are old URL's and no longer required? Clear History All doesn't clean them out. (Firefox 101.0.1 (64-bit) on WIndows 10) thanks

When I ask WordPress to "preview in new tab," I get a File Not Found screen. (See uploaded image.) This works fine in Chrome (which I rarely use) but not in Firefox, so I'm thinking it might be a Firefox issue. The Tablet and Mobile previews work fine, but they don't require a new tab. I thought it might have to do with pop-ups, so I made my blog's URL an exception. That didn't help. Then I disabled the pop-up blocker altogether. That didn't help either. I've never had this problem before although I've been using both Firefox and WordPress for many years. I'm working on an old laptop (current one is kaput), but I think everything's up to date. Windows 10. Any idea what the problem might be? TIA for any help. This is driving me nuts!

Please see https://support.mozilla.org/en-US/questions/1311330 That solution does not work for me. Mac Pro with M1 chip running 12.4 Thanks!

When I try to go the the site https://tvlistings.zap2it.com/ it show top part of page while it tries to retrieve TV listings, but then the whole page goes blank. It still goes blank when in troubleshooting mode.

Works with Microsoft Edge browser. Any ideas?

When on Firefox, I sometimes fill out a form on a website for a variety of reasons, i.e. requesting a document. After doing so, I can find no record that it was sent. My primary email is [edited email from public] @gmail.com. Is that what is used to send it? If so, I cannot find any record of it when I check "sent" items on that account. Please tell me where i can find that record? Steve C

In Firefox, my instructor and student grade sheet no longer displays the horizontal scroll bar to bring more data extended off to the right of the page into view. I have an image attached where the scroll bar should be present. This begin in May sometime, and I'm not sure how to fix. I have tried re-installing fresh a few times, and removed any custom settings that might have been in place. Any and all help would be VERY appreciated as one of colleagues is super frustrated and I would love to find out an answer for both him and myself.