A browser takes computer language - specifically, a language called HTML - and turns it into text and graphics. A browser turns a home computer into a "client" that can read information on companies' web servers.
Anyone who wants to use the web needs a browser, and the market for the programs themselves is fiercely competitive. Two companies dominate: Netscape, which produces Navigator and its sister program, Communicator, and the giant Microsoft, with Explorer (IE4).
The US Department of Justice recently attempted to prevent Microsoft from welding its Explorer browser to the Windows operating system. The DoJ argued that this prevents competition: with most of the world's PCs running Windows, other browser companies will find it hard to compete.
Microsoft responded that the browser is so critical that it has to be integrated into Windows 98, which goes on sale this week. Last week an appeal court upheld its case. But this was just the latest skirmish in the "browser wars" that have raged in the software industry since Microsoft launched Explorer. Microsoft began by giving away Explorer, not just to end users but to internet service providers and electronic commerce sites, such as banks.
Microsoft's strategy has seen Netscape's market share fall to 58 per cent of the home market, and just under 70 per cent of business users. In February this year, Netscape responded by making its browser free.
For all the controversy, both browsers carry out an identical task: accessing web pages. For most day-to-day use, there is little to choose between them.
However, there are cases where the choice of browser does matter. Some on-line banking services recommend Explorer, for example, while Barclaycard's web site only works fully with Communicator, not Navigator or Explorer. There are also internet services that work with one browser only: some features of the Microsoft Network, for example, only work with Explorer IE4.
Lying behind this is a different approach to browsers, and to the web itself. Microsoft's critics say that the company is too wedded to its own, proprietary technologies, while one of the great strengths of the internet is that it is built on open standards.
Microsoft, for example, uses a technology called ActiveX to add functionality to web pages. Sites designed for ActiveX will not work properly for internet users who run one of the Netscape browsers. Nor is ActiveX fully compatible with computers running non-Microsoft operating systems. Apple Mac users will have difficulty with some internet sites, even if they use Explorer to view them.
Netscape contends that web page authors, especially organisations such as banks, should stay with open technologies or risk alienating large numbers of customers. Open standards can take longer to come into force than in-house technologies, but the advantage is compatibility. To make the most of Microsoft's IE4 functions, for example, users have to run Microsoft's Windows 95 or 98 operating systems. Communicator, Netscape claims, is less fussy.
There is evidence that Microsoft is moving closer to the open standards position. The next generation of browsers from both Microsoft and Netscape will support XML, a development of HTML that adds much of the interactivity that ActiveX provides.
This does not mean a truce in the browser wars. Browser market share is important for Microsoft and, especially, Netscape. Starting a browser program takes the internet user to a default home page which, oddly, is almost always the browser maker's. Last year, Netscape made more than $100m from selling space on its home page. With these sums at stake, Microsoft and Netscape will continue to fight their corners.
q: Links: http://www.netscape.com
Stephen Pritchard can be contacted at firstname.lastname@example.org