2012, and some of us still have to support this dinosaur.

header('Content-type: text/html; charset=utf-8');

The cutest Firefox wallpaper !

chrome://browser/content/browser.xul

Click "Inspect" (Icon with a mouse showing a keypress)

In the preview of what the .xul looks like (navigation-toolbar, tabs, bookmarks-toolbar) you select / press on the element you wish to inspect further ..

Good reference

test websites across various browsers and platforms

On mobile we test our sites on Opera Mini, Opera Mobile, Safari on iOs (a few versions), the Browser in Android (many versions), and Chrome on Android 4. But there's another browser you might want to start learning and that's Fennec, the mobile version of Firefox.

If you have to support 1000 different Android Phones there are a few things you can do: run away, test everything on every single one of them or do what <b>Staphanie Rieger</b> advices you to do and learn and understand these devices. It'll save you a lot of time eventually.

[Remove http:// on this link to work]
chrome://browser/skin/browser.css

A great reference for making custom userChrome.css for Firefox.

[Remove http:// on this link to work]
chrome://browser/content/browser.css

A great reference for making custom userChrome.css for Firefox.

Stats are based on aggregate data collected by StatCounter on a sample exceeding 15 billion pageviews per month collected from across the StatCounter network of more than 3 million websites.

Reload/Test userChrome.css without restarting Firefox.