Web Browsing

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One of the most fundamental applications on a computer these days is the web browser. Many people don't view an operating system as complete if it doesn't contain a good browser. This section discusses the web browsers evaluated and chosen for the case study.

The Selection: Konqueror and Mozilla

This case study actually includes two browsers: the Konqueror browser that comes with KDE and the Mozilla browser. Both browsers are modern, fast, and very capable. Here are some details about Konqueror:

• Location: http://www.konqueror.org/

• Version: 3.0

• Package: Included with KDE

• Description: KDE's integrated, componentized media browser

And now some details about Mozilla:

• Location: http://www.mozilla.org/

• Version: 1.0

• Package: Several! See the web site.

• Description: A very high-quality, full-featured open source web browser, editor, and email client.

Konqueror is the built-in browser included with KDE. Konqueror is more than just a web browser; it is also the filesystem browser and manager, and can view a very wide variety of file types such as HTML, PDF, text, and so on. Konqueror really is just a framework that uses KDE components—one for each file type—to display files within the browser. For this reason, Konqueror is very closely integrated with KDE, and is easy to use within that desktop environment. This was the primary motivation for choosing Konqueror as a browser (though Konqueror is also quite fast and robust), so if you're using another environment such as GNOME, you will probably choose another browser.

The Mozilla browser is a full-featured open-source web browser. This is a traditional web browser suite, meaning that it includes an email reader, HTML page editor, and other applications in addition to the browser itself. (Contrast this with Konqueror, which is really just a generic browser and allows other KDE programs to perform the other tasks.) Mozilla is also the core on which Netscape's latest browsers in the 6.x series are based; the Netscape products include some functionality not present in Mozilla, but otherwise the two are functionally very similar. Mozilla is not really integrated with either KDE or GNOME, though it does use the GTK+ widget also used by GNOME. This means that Mozilla will work well within either environment.

The reason both browsers are used in the case study is because occasionally some web pages work better with one than with the other. One reason for this is that sometimes the developers of web sites foolishly choose to use nonstandard content for their pages; for example, they may assume that viewers of the site are using a specific browser. Konqueror and Mozilla both have good support for the various web standards, but their "emulation" of some of these nonstandard quirks and features commonly used by web developers varies. Consequently, Mozilla works on some pages where Konqueror doesn't do a good job (or even locks up or crashes), and vice versa.

Recent versions of both browsers are improved enough that this is becoming less and less common, so you may find that you need only one or the other. Additionally, if you choose an alternative browser, your situation and experience may be completely different.

The Alternatives: Galeon and Opera

There is a quite a selection of web browsers to choose from. Table 14-3 lists many of the most popular browsers available on Linux systems. If you're interested, you should take a look at these browsers and choose the one that best fits your own taste.

Table 14-3: Web Browsers

BROWSER	LOCATION	NOTES
Galeon	http://www.galeon.sourceforge.net	A streamlined, simple browser based on the same core as Mozilla
Opera	http://www.opera.com	A very functional, commercial browser

Browser Plug-Ins

Perhaps just as important as the browser itself is the support the browser has for plug-ins. A plug-in is third-party functionality that is typically distributed in the form of a shared library (or dynamic link library) and is loaded into the browser via some application programming interface (API). Several browser plug-ins are in common use on the web; users without these plug-ins may find many pages inaccessible to them. This section outlines some popular plug-ins available for Red Hat Linux, and installed on the case study system.

Using Plug-ins with the Browsers

A plug-in is only useful if it can be installed and used in a browser. This means that the browser has to implement an API to allow plug-ins a way to be executed. Each browser could potentially implement its own API; however, in this case the makers of plug-ins would have to support a wide variety of APIs.

To avoid this, many browsers—especially browsers on Unix systems—have adopted the Netscape plug-in API. This was the API that Netscape Corporation developed for their Netscape Navigator product. Netscape Navigator was a very popular browser for many years, and so there are a large number of plug-ins available using the Netscape plug-in API. When other browsers implement the Netscape plug-in API, they can take advantage of those plug-ins.

KDE's Konqueror web browser implements the Netscape plug-in API, and in fact uses the same installation directory as Netscape Navigator. So, any plug-ins that get installed for Netscape Navigator can also be used by Konqueror. Additionally, the Mozilla browser is a descendent (at least in spirit if not actual implementation) of Netscape Communicator, and so Mozilla also supports these plug-ins. Many of the alternative browsers do, as well.

The following sections discuss two specific plug-ins that are available and work with Konqueror and Mozilla, but in general any plug-in that uses the Netscape plug-in API should work, with varying degrees of success. These plug-ins are Macromedia Flash and Java.

Note 

Sometimes bugs or idiosyncrasies can cause plug-ins to crash or even not work at all.

The Macromedia Flash Plug-In

Macromedia's Flash format is a way to produce games, animations, or interactive utilities, and publish them on the web so that they are available to users. Users access these applications through their web browser, rather than by downloading and installing them. The applications are executed by a plug-in that runs in the users' browsers. Flash applications are typically fairly lightweight, and are usually used for short animations or simple games or to spice up a web site.

Flash is extremely popular, but it's not an entirely open standard, which is a concern to many people. Whether you like or dislike Flash, though, it's a reality of the web. Red Hat Linux includes Flash in the package netscape-common. If you have that package installed already, you have support for Flash.

If you don't have that package and don't care to install it (perhaps because you don't use the now-dated Netscape Communicator), then you may need to visit Macromedia's site at http://www.macromedia.com and download and install the Flash plugin yourself. You would also need to do this if you wish to upgrade to a later version of the plug-in. Installation is quite easy and generally involves extracting the contents of the .tar.gz file from Macromedia into a directory—usually ~/.netscape/plug-ins—and then instructing Konqueror (or other browser) to refresh its list of installed plug-ins. Macromedia's distribution file contains full documentation.

The Java Plug-In

Chapter 13 discussed the installation of the Java Development Kit (JDK). Part of the Java API includes an applet API. An applet is simply a program written in Java that is intended to be run from within a web browser. Just as with Flash, support for Java applets requires a browser plug-in.

With recent versions of the Java platform, a plug-in is available that connects the installation of Java to the browser. This plug-in is not included with the installations of KDE or Mozilla (since Java isn't, either), but it is included with the JDK. Installing the plug-in is pretty easy, and instructions are available from Sun Microsystems' web site at http://www.java.sun.com.

Installation is quite simple with Konqueror. The JDK already contains everything you need—you simply need to set up your browser. If you create a symbolic link from your ~/.netscape/plugins directory to the plug-in library (which happens to be /opt/java/jdk/jre/plugin/i386/ns4/javaplugin.so) and then refresh Konqueror's list of installed plug-ins, you'll be all set! It's as easy as this command:

 $ ln -s /opt/java/jdk/jre/plugin/i386/ns4/javaplugin.so ~/.netscape/plugins 

The only caveat to remember when installing this plug-in is to use the correct path to the JDK. Chapter 13 installed the JDK in such a way that it can be upgraded easily. Specifically, the JDK was installed in a subdirectory of /usr/local/java— for example, /usr/local/java/sun-jdk-1.3.1 for JDK version 1.3.1—to permit multiple JDKs to be installed. A symbolic link was created in /opt/java/jdk pointing to the JDK installation that is to be the default for the system.

However, only one Java plug-in can be enabled at a time, so be sure you're installing the correct plug-in. Also, make sure you remember to upgrade your plug-in installations if you upgrade the JDK.

Just as important as functional core software is functional hardware (and implicitly the low-level software that drives the hardware). The next section discusses how to configure and use some common hardware devices with Red Hat Linux.

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