iTechNote

With the release of Firefox 2.0 (which should be official on the afternoon of Tuesday, 24th October 2006), the web browser war is once again heat up. The rush of RC3 to final after just a week of release again signifies the worries of Firefox community about IE7’s challenge.

Apart from the user interface differences, lest we forget the differences at the core, which is called the layout engine or rendering engine. It takes web content (such as HTML, XML, image files, etc.) and formatting information (such as CSS, XSL, etc.) and displays the formatted content on the screen. It “paints” on the content area of a window, which is displayed on a monitor or a printer.

The layout engine exists not only in web browsers but also email clients, media players with mini-browser and any applications that can display web contents.

There are 4 major rendering engines on the market.

• Trident - Internet Explorer 4 and above
• Gecko - Mozilla Firefox
• KHTML & WebCore - Konqueror, Safari
• Presto - Opera 9

Trident

Trident was first introduced with the release of Internet Explorer version 4 in October 1997, has been steadily upgraded and remains in use today. IE7 is still using Trident albeit an upgraded version called Trident V. Trident V remains significantly less compliant to open Internet standards than Gecko, KHTML, WebCore and Presto. It also remains part of Windows and any security vulnerabilities will still potentially expose the OS.

Gecko

Gecko is designed to support open Internet standards licensed under MPL/GPL/LGPL triple license. Firefox 2 will be based on continued development of the Gecko 1.8 branch created for Firefox 1.5. The goal is that Firefox 1.5 and 2 are compatible from a web developer’s point of view. The content of the Firefox 2 release is to be mostly user-focused and performed on the 1.8 branch.

KHTML & WebCore

KHTML is faster than the Gecko layout engine but less well known. Many websites fail to support it or claim no support even if the site does work. The engine was adopted by Apple in 2002 for its Safari web browser under the name of WebCore (a component of WebKit).

The new S60 web browser for Nokia Nseries is based on WebCore. Nokia team chose WebCore over Mozilla’s Gecko for its much smaller code size, smaller cpu/memory needs and better written source code.

Presto

Presto was first released on January 28, 2003 in Opera 7.0 for Windows. Not much info has been released to the public about the rendering engine. It is the most versatile of all that runs on Windows, Mac OS X, variants of UNIX and whole spectrum of mobile platforms.