This appendix provides a brief overview of the mainstream browsers in general use at the time of writing, including a little history about them, estimated market share, and how standards-compliant they are (along with whether they pass the Web Standards Project Acid2 Browser Test, at www.webstandards.org/action/acid2/).

Firefox

Full name: Mozilla Firefox.
Initial year of release: 2004 (as 1.0).
OS: Windows, Mac OS X, Linux (unofficial ports to various other systems exist).
Website: www.mozilla.com/firefox/.
Market share estimate: 10–15%.
Trend: Steady growth.
Engine: Gecko.
Compliance: High. Firefox makes an excellent base for development, although as of 2.0, it fails a few advanced elements of the Acid2 Browser Test.
Comments: Initially devised as an unofficial branch of the Mozilla project, Firefox’s aim was to be a compact, speedy browser, devoid of the feature-creep evident in its parent. Initially innovative, bringing tabbed browsing and incremental find (findas- you-type) functionality to the masses, Firefox’s market share rapidly grew as standards-aware websites formed an aggressive switch marketing campaign, designed to tear complacent users away from Internet Explorer. Should you work with Firefox, I highly recommend you install Chris Pederick’s Web Developer toolbar, available from www.chrispederick.com/work/web-developer/.

Internet Explorer

Full name: Windows Internet Explorer.
Initial year of release: 1995.
OS: Microsoft Windows.
Website: www.microsoft.com/ie.
Market share estimate: Around 80%. (This figure is combined, split more or less evenly between Internet Explorer 7 and Internet Explorer 6, with a low and diminishing number of users running version 5.x.)
Trend: Slow decline.
Engine: Trident.
Compliance: Reasonable for version 7, although it dramatically fails Acid2. Poor for version 6 and before, which require fixes for many advanced CSS properties and values.
Comments: Despite being initially ignored, Microsoft’s Mosaic-derived browser became embroiled in the infamous browser wars of the late 1990s, regularly adding new features and capabilities to eclipse rival Netscape Navigator. With the battle won by 1999, Microsoft’s browser seemingly lapsed into a semicomatose state. Version 5’s standards support was dire (unlike the Mac version, which was later canceled), and while version 6 was an improvement, it still lagged behind its rivals, including the then-new Firefox, resulting in its previously all-dominant market share (which rose to a high of around 95%) being hit hard for nearly two years. In late 2006, the final public release of version 7 appeared, with much-improved standards support (although this aspect remains inferior to that of its rivals) and features available in rival browsers (such as tabbed browsing). A Microsoft-produced developer toolbar is available for version 7 of Internet Explorer; Download.

Opera

Full name: Opera.
Initial year of release: 1996 (first public release).
OS: Windows, Mac OS X, Mac OS, Linux, BeOS, Solaris, and others.
Website: www.opera.com/.
Market share estimate: Under 2%.
Trend: Stable.
Engine: Presto.
Compliance: Excellent. Passes Acid2, making it an excellent alternative to Firefox for a development base.
Comments: Starting life as a research project for a Norwegian telecom company, Opera has grown into a feature-packed, standards-compliant browser. Its innovative features—some of which are of direct benefit to developers—often lead its rivals, although the browser has been hampered over the years by a cluttered and superficially complex interface, and the browser for a long time identifying itself as Internet Explorer. Because of this, market share figures for Opera were—and indeed possibly still are—artificially low. However, in terms of reach, Opera has plenty of potential: there are versions of the browser for a massive range of systems, including for handheld devices. A developer toolbar is available from www.operawiki.info/WebDevToolbar.

Safari

Full name: Safari.
Initial year of release: 2003.
OS: Mac OS X, Windows.
Website: www.apple.com/safari/.
Market share estimate: About 4%.
Trend: Slow growth.
Engine: KHTML.
Compliance: Excellent, with reservations (see comments). Passes Acid2, making it suitable for a development base.
Comments: Most likely developed as a reaction to Microsoft axing Internet Explorer for Mac, Safari rapidly became the primary browser for Mac users. Its clean interface complements the KHTML engine, which is one of the most compliant in existence. (Indeed, Safari was the first browser to pass Acid2.) Although initially available to Mac users only, June 2007 saw the first beta of Safari for Windows, primarily intended as an aid to Windows-based developers creating content for Apple’s iPhone. Safari has some shortcomings regarding JavaScript support, and its method of anti-aliasing text is significantly different to other browsers. Prior to version 3, CSS borders and colors for form fields and buttons were ignored, the Mac OS Aqua equivalents instead being “forced.”

Other browsers

A number of other web browsers exist, although their market share is so minimal as to be considered all but insignificant. A possible exception to this is Linux-based Konqueror, although with its KHTML engine, you should expect similar results to those in Safari. Elsewhere, some browsers are based on Gecko (such as SeaMonkey/Mozilla and Flock), some on Trident (such as AOL Explorer/OpenRide), and one on both (Netscape Browser).