Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

On Mozilla Firefox (on GNU/Linux) with default font and UTF-8 encoding, I am seeing some websites, such as GitHub, display weird characters across the page.

Weird behavior

Under a different browser, such as WebKit based, the site looks normal.

What is causing these icons or glyphs to appear when I view such sites?

share|improve this question
Have you allowed its fonts to be loaded? – random Feb 5 '13 at 22:00
@random Oh dear, who unchecked that? Shame on me. Ok, this is the answer. Put it as answer and get your karma :) – Dacav Feb 5 '13 at 22:17
up vote 3 down vote accepted

If a website viewed in Firefox looks like it's all jacked up but in other browsers it's okay then you may have switched off allowing the site to download and/or display a custom font.

This is usually the case if you are seeing gibberish like a small box with numbers and letters on top of each other on parts of the website where you would expect to see custom icons.

To fix this, go to

Tools → Options → Content → Fonts & Colors → Advanced

Make sure the following has a check mark in the box:

☑ Allow characters to choose their own fonts, instead of my selections above

OK, OK, and you will now see the font icons the site has set up.

share|improve this answer
Note: This also applies to Firefox' internal PDF viewer (pdf.js). If "Allow characters to choose their own fonts[...]" is disabled, most PDF files will look very weird, because all text will use the default font. – sleske Feb 6 '13 at 23:35

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.