A web browser, as mentioned earlier, is the program you use to view pages and navigate the World Wide Web. A wide array of web browsers is available for just about every platform you can imagine. Most browsers are freeware or shareware (try before you buy) or have a lenient licensing policy. Microsoft Internet Explorer, for example, is included with Windows and Safari is included with Mac OS X. Mozilla Firefox, Netscape Navigator, and Opera are all available for free. Currently, the most widely used is Microsoft Internet Explorer (sometimes called just Internet Explorer or IE). Despite the fact that Internet Explorer has the lion's share of the market, however, it isn't the only browser on the Web. This point will become important later, when you learn how to design Web pages and learn about the diverse capabilities of different browsers. Assuming that Internet Explorer is the only browser in use on the Web and designing your pages accordingly limits the audience you can reach with the information you want to present.
Choosing to develop for a specific browser, such as Internet Explorer, is suitable when you know a limited audience using the targeted browser software will view your website. Developing this way is a common practice in corporations implementing intranets. In these situations, it's a fair assumption that all users in the organization will use the browser supplied to them and, accordingly, it's possible to design the web pages on an intranet to use the specific capabilities of the browser in question.
What the Browser Does
The core purpose of a web browser is to connect to web servers, request documents, and then properly format and display those documents. Web browsers can also display files on your local computer, download files that are not meant to be displayed, and in some cases even allow you to send and retrieve email. What the browser is best at, however, is dealing with retrieving and displaying web documents. Each web page is a file written in a language called the Hypertext Markup Language (HTML) that includes the text of the page, a description of its structure, and links to other documents, images, or other media. The browser takes the information it gets from the web server and formats and displays it for your system. Different browsers might format and display the same file in diverse ways, depending on the capabilities of that system and how the browser is configured.
Retrieving documents from the Web and formatting them for your system are the two tasks that make up the core of a browser's functionality. Depending on the browser you use and the features it includes, however, you also might be able to play Flash animations, multimedia files, run Java applets, read your mail, or use other advanced features that a particular browser offers.
An Overview of Some Popular Browsers
This section describes the most popular browsers currently on the Web. They're in no way the only browsers available, and if the browser you're using isn't listed here, don't feel that you have to use one of these. Whichever browser you have is fine as long as it works for you.
Microsoft Internet Explorer
Microsoft's browser, Microsoft Internet Explorer, is included with Microsoft Windows. It was also included with the Mac OS, but has since been discontinued. You can still install and use other browsers if you want, but if you're not picky, you don't need to do anything more.
If you're serious about web design, you should install all the popular browsers on your system and use them to view your pages after you've published them. That way, you can make sure that everything is working properly. Even if you don't use a particular browser on a day-to-day basis, your site will be visited by people who do. If you are interested in checking cross-browser compatibility issues, you should start with Microsoft Internet Explorer and Mozilla Firefox, and perhaps include Opera as well.
Microsoft Internet Explorer has become the most widely used web browser, in large part due to the fact that it has been tightly integrated with the latest versions of Windows. As of January 2006, Internet Explorer makes up more than 80% of the overall browser market. Figure 1.4 shows Internet Explorer running under Windows XP.
Figure 1.4. Microsoft Internet Explorer (Windows XP).
Mozilla Firefox is the new kid on the web browser block. In 1998, Netscape Communications opened the source code to their web browser and assigned some staff members to work on making it better. Seven years and many releases later, the result of that effort is Mozilla Firefox. Netscape Communications, since acquired by America Online, no longer has any official ties to the Mozilla Foundation, which is now an independent nonprofit organization.
Microsoft released Internet Explorer 6 in October 2001. Firefox and its predecessor Mozilla have seen many revisions over that time, and currently offer more comprehensive support for web standards than does Internet Explorer. Firefox is available for Windows, Mac OS X, and Linux, and is a free download at http://www.mozilla.com.
Internet Explorer still dominates the web browser market, but Firefox is becoming increasingly popular, especially with people who create websites.
Once the dominant web browser, Netscape Navigator is now a version of Mozilla Firefox that has been modified to have the Netscape brand rather than the Mozilla brand. In terms of how they display web pages, Netscape Navigator and Mozilla Firefox are identicial. You can download Netscape at http://browser.netscape.com.
The important thing to remember about Netscape is that the browser has a long history, and once dominated the market. Netscape went nearly four years between browser releases, and at one time Netscape 4.7 was extremely popular. Unfortunately, now it exists mainly to cause pain to web designers. The problem with Netscape 4.7 is that it's old, and its support for current web standards is woefully lacking. With Firefox, much effort was put into making it adhere as closely as possible to published standards. When Netscape 4.7 was released, Netscape was taking a more cavalier attitude toward standards. The bottom line is that pages that look great in Internet Explorer, Firefox, and other current browsers can look awful in Netscape 4.7. You'll have to decide whether you take this into consideration as you design your pages.
When it comes to browsers, Microsoft Internet Explorer and Mozilla Firefox are the big two. And in terms of market share, Internet Explorer dominates, but there are plenty of other browsers floating around as well. You'd think that given the fact that the browser market has been dominated by Microsoft or Netscape almost since its inception, there wouldn't be a lot of other browsers out there, but that's not the case.
For example, Opera (http://www.operasoftware.com/) has a niche market. It's small, fast, free, and available for a number of platforms, including Windows, Mac OS X, and Linux. It's also standards compliant. Apple has developed a browser named Safari that is the default web browser for Mac OS X. For UNIX users who use KDE, there's Konqueror. There are various Mozilla offshoots, such as Camino for Mac OS X, and Flock, a browser derived from Firefox that is integrated with a number of websites that enable you to publish your own content on the Web. Likewise, command-line browsers such as Lynx and Links are available to provide an all-text view of web pages. There are also a number of browsers that provide access to the Web for people with various disabilities; I'll discuss them in detail in Lesson 17, "Designing for the Real World." It makes sense to code to common standards to accommodate all these types of browsers.
Using the Browser to Access Other Services
Internet veterans know that there are dozens of different ways to get information: FTP, Usenet news, and email. Before the Web became as popular as it is now, you had to use a different tool for each of these, all of which used different commands. Although all these choices made for a great market for How to Use the Internet books, they weren't very easy to use.
Web browsers changed that. Although the Web itself is its own information system with its own Internet protocol (the Hypertext Transfer Protocol or HTTP), web browsers can read files from other Internet services also. Even better, you can create links to information on those systems just as you would create links to web pages. This process is seamless and available through a single application.
To point your browser to different kinds of information on the Internet, you use different kinds of URLs. Most URLs start with http:, which indicates a file at an actual website. To download a file from a public site using FTP, you'd use a URL like ftp://_name_of_ site/directory/filename. You can also view the contents of a directory on a publicly accessible FTP site using an ftp: URL that ends with a directory name. Figure 1.5 shows a listing of files from the iBiblio FTP site at ftp://ftp.ibiblio.org/.
Figure 1.5. A listing of files and directories available at the iBiblio FTP site.
To access a Usenet newsgroup through your web browser (thereby launching an external news-reading program), you can simply enter a news: URL, such as news:alt.usage.english.
You'll learn more about different kinds of URLs in Lesson 5, "Adding Links to Your Web Pages."