Browser Support for CSS | Page 6 | WebReference

Browser Support for CSS | Page 6

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Browser Support for CSS


The Opera browser was developed by Opera Software of Oslo, Norway, and runs on Microsoft Windows, Mac OS X, and Linux and Unix-like operating systems. The current version is Opera 8.5, and it uses a layout engine named Presto. Presto has good support for CSS, which isn't that surprising considering that Håkon Wium Lie, one of the creators of the CSS specification, is a long-time Opera employee. Opera is also very customizable, and has good support for user-defined style sheets and user configuration options.

Did you Know?

You can download Opera for a wide variety of platforms from

In general, there are very few situations in which you will need to provide special code for Opera only. Opera's CSS 2.1 support is generally quite solid and it does CSS-based layout without major problems.

By the Way

At the time of this book's writing, a preview version of Opera 9 is available for testing. The new version of Opera promises even better support for CSS; in late March, 2006, the Web Standards Project announced that Opera 9 passed the Acid2 test. Because of the unstable nature of pre-release software, this book doesn't cover any Opera 9 CSS quirks or bugs.

Early versions of Opera quickly gained a reputation for excellent CSS support—relative to the existing browsers in the market. The 5.0 and 6.0 versions have seen Opera drop back into the middle of the pack for CSS support; there are some serious CSS limitations and bugs in Opera versions before Opera 7.

Fortunately, Opera users tend to be well informed about new browser releases and transition relatively quickly to newer, less buggy versions. For this reason, the older versions of Opera are not a serious problem at this time and rarely need any special attention.


Safari is Apple Computer's Web browser for the Mac OS X operating system. The layout engine in Safari is called WebCore and is based on the KHTML layout engine from Konqueror (which you'll learn about in just a moment). There are two current versions of Safari—Safari 2 runs on Mac OS X version 10.4, and Safari 1.3 is for Mac OS X version 10.3. The layout engine is almost the same between the two versions, so for CSS purposes they're effectively the same browser.

Safari supports nearly all of CSS 2.1, including advanced selectors and CSS-based layout. You won't have many problems from Safari when you write standard CSS. In April 2005, it was reported that Safari 2 had successfully passed the Acid2 test.

Older versions of Safari had numerous CSS bugs, but Apple's software developers have been diligently rooting them out. The Safari browser is included with the Mac OS X operating system, and is automatically updated by Apple's software update program. This means very few users will have-out-of date versions of Safari; you won't have to worry about older, buggy versions.

Did you Know?

Apple's website for Safari is, and you can also install the most recent version through Software Update.


Konqueror is an open-source browser developed as part of the K Desktop Environment (KDE) by volunteers for Linux, BSD, and other Unix-like operating systems. In addition to being a Web browser, it also functions as a file manager and file viewer.

Konqueror uses a layout engine called KHTML, which was incorporated into Apple's WebCore layout engine. Konqueror also can operate in a mode where it uses Mozilla's Gecko layout engine.

In general, Konqueror's support for CSS is good, thanks in part to the contributions of Apple's WebCore developers back into the KHTML project, and in part because of the efforts of KDE's volunteers. In June 2005, Konqueror passed the Acid2 test from the Web Standards Project. Because of this high level of CSS support and Konqueror's small user base, you likely will never have to pay any special attention to Konqueror.

Did you Know?

You can download Konqueror from the KDE website at


WebCore is the name of Apple's KHTML-derived layout engine for Mac OS X, which has been incorporated into other applications that need HTML rendering functions. Such applications have no more and no fewer problems than does Safari when it comes to CSS display; whatever you do for Safari will benefit these browsers as well.

The OmniWeb browser is one of the older small browsers still around, originally written in 1995 for the NeXTSTEP platform. Created by the Omni Group, OmniWeb first used its own proprietary layout engine, but in 2003 switched to using Apple's WebCore.

Did you Know?

OmniWeb is available for Mac OS X from

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