Internet Explorer
(Screen Shot)As of this writing, Internet Explorer is the most popular web browser. It comes installed on both Windows and Macintosh computers. For the most part, the more recent versions of Explorer have more reliable support for style sheets, and offer more advanced javascript functions. Internet Explorer 5 also supports XML and a draft of the XSL standard, although of course enough people do not have Internet Explorer 5 for you to rely on these features yet.
Netscape Communicator
(Screen Shot)As of this writing, Netscape Communicator is a close second in usage to Internet Explorer. Netscape is still supported on a wider range of platforms, as Internet Explorer is not supported for many UNIX variants or for alternative operating systems. Netscape has a few idiosyncrasies with its default style sheet settings, such that margins are often quite bigger than intended.
iCab
(Screen Shot)iCab is a new web browser for Macintosh computers. At this time the browser is still in the development phase. Some features, such as JavaScript and Cascading StyleSheets Level 2 (CSS2), are not yet supported. iCab has many of the same features that Netscape Communicator and Internet Explorer have. A unique feature of iCab though, is that it creates an error report on the web page being viewed. This error report is based on HTML specifications declared by the World Wide Web Consortium (W3C). The error report is very helpful in teaching a HTML programmer to write good code that will display as intended on all browsers. For a detailed instructions on using iCab to check and correct the syntax of a web page, see Tasks: Checking the Syntax of an HTML File.Differences Between Platforms
Although many versions of browsers developed for different platforms share the same name and version number, there are often inconsistencies in their behavior. Beyond slight differences in the margins and fonts used by default, there may be problems with printing, java and javascript support. If you choose to use movies, sounds, or other media, you may have to worry about whether plug-ins are available for a particular platform. Your best defense against common problems with platform incompatibilities is to test your pages on at least one variant of Windows and the Macintosh Operating System.Differences Between Browsers
Because HTML itself and image formats were standardized early on, most browsers support the basic features of HTML in a predictable way. Newer features, such as style sheets, alternate image formats (such as PNG), javascript, and java are less well supported. There are a number of methods to enable cross-browser javascript and style sheets, the best way to avoid problems is to use these technologies sparingly, and to test pages on at least Netscape and Internet Explorer.
There are a number of pages that discuss the differences in the way the major browsers support these advanced features. The best reference for style sheet support can be found at http://www.webreview.com/wr/pub/guides/style/mastergrid.html. This guide covers how well the latest versions of different browsers support common style sheet commands. A Java and JavaScript compatibility chart provided by Customer Insight Company can be found http://www.vamp.nl/artikelen/lezingen/Roelof_Andre/13Ways/dre/CompChart/browsers.htm.