Both FireFox and Google Chrome (but not Internet Explorer) have been showing black diamonds with question marks in them for some time. It's not an encoding issue, as changing character encoding doesn't work. I don't know what caused it, as it all of a sudden started out of the blue. My network.http. in about:config are all default. I've tried scanning for malware, including in safe mode with the internet disconnected. Nothing has made a difference. Please help me, as this problem is incredibly hard to Google and I have no idea what to do.
Can you spot a pattern as to which fonts are involved? Sometimes font files become corrupted or browsers substitute other similarly named fonts.
The FontInfo extension adds a right-click context menu item to see what font Firefox actually is using for a selection of text: https://addons.mozilla.org/firefox/ad.../fontinfo/. That might help in isolating the problem.
See cor-el's reply : https://support.mozilla.org/en-US/questions/930473
Can you post a link to a web page where you see these diamonds and possibly attach a screenshot?
Which encoding settings did you try?
A diamond with a '?' usually indicates that a character is missing in the font that is used on a website or the wrong encoding is used. You can also get the '?' on websites that use an 8 bit encoding like ISO-8859-1 or an encoding like Windows-1252.
Screen shot: http://postimg.org/image/gynyypb77/
As for encodings, I've tried switching from Unicode(UTF-8) to Western(ISO-8859-1) and and to every one with Western, Japanese and Korean in its name out of desperation.
The server sends the page in your link as Unicode (UTF-8) and that works for me.
This can be a problem with the font that is used to display the text.
You can use this extension to see which fonts are used for text that is selected (right-click: "Show fonts in selection").
You can try different default fonts and temporarily disable website fonts to test the selected default font.
The more I look at your image, the more broken it looks. You can see parts of HTML tags where they should not be visible, such as the /span> in the top bar and after the date (in red); the drop-down that has /option>; and in the video descriptions where you see strong or href=.
Something is corrupting the page, maybe an extension, or proxy/filter service, or security software?
To rule out an extension, you could try Firefox's Safe Mode. That's a standard diagnostic tool to bypass interference by extensions (and some custom settings). More info: Troubleshoot Firefox issues using Safe Mode.
You can restart Firefox in Safe Mode using
Help > Restart with Add-ons Disabled
In the dialog, click "Start in Safe Mode" (not Reset)
A website I visited through Firefox shows interminable little black diamond-shaped diagrams with a white question mark inside. Using IA and Chrome they do not appear on that website. They do not seem to appear on other websites through Firefox. Is it the fault of the visited website or does Firefox have a bug. I'm no good with complicated answers such as I have seen here.
Can you post a link to a publicly accessible page that doesn't require authentication (signing on)?
Did you check which encoding is used (Firefox > Web Developer > Encoding)?
You usually see the diamonds if there is a wrong encoding used like UTF-8 instead of Western encoding that doesn't include the character.
Also make sure that the default encoding is Western (ISO-8859-1)
I'm sorry, but I cannot understand a word of what you have said. It is like a foreign language But thank you for trying. I have only seen these things on the same website of which I am a member. -never anywhere else. I use Firefox a lot. But when I accessed that website through two other browsers, just to see, the black diamonds did not appear - only through firefox. I do not experience this phenomenon anywhere else when I use firefox.