Remove header from printing

Type about:config in the URL bar and hit Enter. If you see the warning, you can confirm that you want to access that page.

Filter = header Right-click each of those prefs and select Modify, then backspace or use Delete to wipe the characters – then click OK.

Firefox is really nothing special, interesting, or useful. Gecko is.

Firefox is a complete system. It is a web browser, and only a web browser. You can write plugins for it, sure. Those plugins can do an awful lot. But at the end of the day, no matter how many plugins you add, it’s still a web browser. For a plugin to remove web browser behavior is quite difficult. You can write all sorts of extensions for it, even games or IRC clients, but you really cannot get away from the fact that it is a web browser.

It’s not Firefox that makes Firefox powerful, though. It’s the engine underneath it, Gecko. Gecko is an engine that supports rendering all kinds of common Internet standards, like HTML, CSS, SVG, RDF, MathML, XSLT, etc. It has pluggable support for more markup systems, such as XForms. It supports Javascript natively for manipulating documents in all of those languages.

And that’s it. Gecko provides no UI. It provides no UX. It provides no reason for an end user to give a damn that it exists. What it does provide is XUL: The XML User interface Language. It is an XML-based markup language for defining the structure of an arbitrary user interface which is then manipulated using Javascript. It is a framework for building stuff that leverages Internet technologies: (X)HTML, CSS, SVG, XSLT, Javascript, etc.

Gecko began life as the engine of the big and slow and annoying Netscape 6. Eventually, some developers said “screw this”, took the engine, and build a new, leaner, fewer-featured-but-extensible web browser out of it. They called it Phoenix, because it was a browser rising from the ashes, but due to various trademark disputes it was renamed several times until it eventually settled on Firefox. But the real power of the system, and the reason it is so extensible, is Gecko and XUL.

Those technologies, however, are not bound to just web pages. Because Gecko is a generic framework, it can be used for a wide variety of applications: Firefox the web browser, Thunderbird the mail client, Seamonkey the internet suite, Songbird the music player, Sunbird the calendaring program, Komodo the multi-language IDE, DevHelp the documentation browser, the Celtx Media pre-production suite, all are based on that same core framework of Gecko. And only one of them looks anything like a web browser, but all of them are extensible. And most of them, I wager, the original Gecko developers back in 1998 never even dreamed of enabling.