I know a lot of other people also have asked this question but I feel like it's easier for me to understand if told to 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 selected text.

• fontinfo: https://addons.mozilla.org/firefox/addon/fontinfo/

You can do a font test to see if you can identify corrupted font(s).

• http://browserspy.dk/fonts-flash.php?detail=1

• https://support.mozilla.org/kb/Changing+fonts+and+colors

Yoo can check this by right click and selecting "inspect element" , web pages would be shown as italic if it is set to italic mode in background

(link to blog removed by Moderator)

It says "Arial Italic", using the Font Info. add-on, but when I checked my Fonts settings (under Firefox>Options>Content>etc.) there wasn't any font that I chose or chosen by default that is close to being Italic...

I right-clicked and didn't see any "Inspect Element"...

Firefox 9 doesn't have the inspector.

Any particular reason why you haven't update to the current Firefox 14.0.1 release?

It is important to update to the latest version of Firefox and add-ons to get the latest bug fixes and security updates.

• https://support.mozilla.org/kb/update-firefox-latest-version

What is the current default font setting?

You can try different default fonts and temporarily disable website fonts to test the selected default font.

• Tools > Options > Content : Fonts & Colors > Advanced
• [ ] "Allow pages to choose their own fonts, instead of my selections above"

If you have identified the not working font then you need to reinstall that font.

Hi cor-el,

I tried it. That didn't do it for me. I'm using Firefox 15 under Windows 7 and it still changes font sizes randomly while I'm typing an message on the Yahoo webmail interface.

- Art

This thread is not about font sizes, but about a different font being used, in this case an italic font.
If the font size changes then this is more likely caused by coding errors in the Yahoo! text editor or you use the cursor keys and get out of the current size formatting paragraph or span or you are deleting formatting code.

Nope, updated my Firefox and the font is still italic, even this reply I'm typing. And thanks for letting me know that there's an update, I wasn't aware. Asking another question here but how can I check which version of Firefox am I using?

It's no long in italic if I uncheck the box "Allow pages to choose their own fonts, instead of my selections above". That is if I use OTHER fonts rather than all the Arial variants, right now I'm using Verdana which I kind of like. But hey, this is the least I could ask for... Thanks for your help!

If it is the Arial font that isn't working properly then you need to reinstall that font.

I'm not sure that the problem is a corrupt font, since all other browsers (Safari and Chrome in my case) appear to display the fonts correctly.

I had the same problem for over a year. Fonts were fine in Google Chrome but not in Firefox. You might also try MS Word. My Arial font was always italic in MS Word too.

Are you running windows 7 on an HP computer by any chance? It seems this is a common problem on HP computers. If so the probem is most likely an Arial font problem. Your arial font folder probably has the bold and italicis fonts but no longer has the regular font. You need to restore arial.ttf.

Either use your restore disk or get this download from microsoft: http://www.microsoft.com/en-us/download/details.aspx?id=16083