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Java Unleashed

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Chapter 8


Netscape is without a doubt the largest player in the Web browser business. It is insanely popular Netscape Navigator Web browser dwarfs all other browsers in terms of market share, with no signs of any significant losses in the near future. It is certainly going to see some fierce competition, but Netscape is staying on top of things and integrating the latest technology into Netscape Navigator.

Java currently is the most important of these new technologies. With the advent of Navigator 2.0, Netscape has provided complete support for the Java language. Additionally, Netscape has collaborated with Sun to create a scripting language based on Java called JavaScript. Together, these two technologies promise to keep Netscape firmly rooted as the king of the Web browser hill. For Web developers, this means that interactivity on the Web has finally comeof age.

As of this writing, the Macintosh and Windows 3.1 versions of Netscape Navigator still do not have support for Java. However, you can expect support to arrive for these platforms in the near future.

In this chapter, you learn about how Java and JavaScript impact Netscape’s new product line, especially the Navigator Web browser. Netscape Navigator 2.0 provides very strong support for Java and JavaScript, as you’ll see.

Netscape Products

Before getting into the Java-specific aspects of the latest release of Netscape Navigator, it’s important to bring you up to date with this version of the popular Web browser, along with other Web-related products being offered by Netscape. First, Netscape has opted for two different versions of Navigator, standard and gold. Navigator 2.0 is the logical upgrade to the original Navigator Web browser. Navigator Gold 2.0 includes Navigator 2.0, along with a Web development environment, enabling users to edit HTML files graphically.

Additionally, Netscape is releasing Live Wire, which is a Web development environment that provides the tools necessary to create and manage Web sites. Live Wire includes Navigator Gold and the JavaScript scripting language. And if Live Wire isn’t enough for you, Netscape also has Live Wire Pro, which adds to Live Wire the capability to browse, search, and update relational databases.

To summarize, Netscape is offering the following Java-supported products to the Webcommunity:

Navigator 2.0

Navigator Gold 2.0

Live Wire

Live Wire Pro

Netscape’s new Web tools will no doubt set the standard for others to follow. With its new features and wide support for new technologies, Navigator 2.0 should easily match the popularity of its predecessor. However, as impressive as the new Navigator browser appears to be, Netscape may ultimately gain more from the release of Navigator Gold and Live Wire. The early integration of Java into all of these products has set the stage to bring Java to the Web in full force.

Navigator 2.0

Navigator 2.0 is the first major upgrade to the immensely popular Netscape Navigator Web browser. This upgrade includes improved e-mail, newsgroup, FTP, and navigation capabilities, along with inline multimedia plug-ins. The inline multimedia plug-ins include support for Adobe Acrobat PDF documents and Macromedia Director presentations, among others. The Navigator plug-in supporting Macromedia Director presentations is called Shockwave. Additionally, a plug-in supporting Apple’s QuickTime multimedia standard is expected soon. Navigator 2.0 is also the first browser to provide complete Java support. Figure 8.1 shows what Netscape Navigator 2.0 looks like.

Figure FIGURE 8.1.

Netscape Navigator 2.0.

The new Navigator update also adds enhanced performance through client-side image maps, progressive JPEG images, and streaming audio and video. Its new security features include digital ID, secure courier for financial transactions, and secure e-mail and news. Navigator 2.0 also features advanced layout capabilities, including frames, which enable the display of multiple, independently scrollable panels on a single screen. Each of these panels can have a different Web address as its source.

Navigator Gold 2.0

Navigator Gold 2.0 is a tool built around Navigator 2.0 that enables Web developers to design and edit HTML documents graphically. The HTML editor is integrated into the Navigator environment, and effectively combines editing and viewing functions into one application. It will be interesting to see how Navigator Gold is perceived by the Web development community, as it is really the first attempt by a major Web player at providing a graphical HTML development system.

Live Wire and Live Wire Pro

Netscape’s Live Wire goes a step beyond Navigator Gold by providing an environment that lets developers graphically build and manage applications and multimedia content for the Internet. Live Wire’s graphical design approach is aimed at simplifying the management of complex Web document hyperlinks. Live Wire includes Navigator Gold and the JavaScript scripting language. Netscape is also offering Live Wire Pro, which adds database connectivity to Live Wire. With Live Wire Pro, users can interact with relational databases on the Web.

Netscape Support for Java

Netscape Navigator 2.0 is the first major Web browser to provide support for Java. Although this aspect of Navigator has generated a significant amount of press attention, it’s important to realize that the bulk of Navigator’s Java support takes place behind the scenes. Many Navigator users will likely see Web pages come to life and not fully realize that Java is the technology making it all happen. The point is that the Java support in Navigator affects the content of Web pages viewed in Navigator a great deal, but affects the Navigator interface and options very little.

Because the Java support in Navigator is a behind-the-scenes issue, it isn’t always clear what parts of a Web page are using Java. If you saw a Java Web page and didn’t know anything about Java, you might just think that Web page developers were pulling off neat tricks with CGI or some other scripting language. But you are well on your way to becoming a Java expert, so you know better; Java opens the door to doing things that are impossible with scripting languages like CGI.

Java programs appear in Navigator as applets that are embedded in Web pages. Java applets are referenced in HTML source code using a special APPLET tag. Navigator parses these tags and automatically launches an internal Java interpreter that executes the Java applets. By implementing a Java runtime interpreter, Navigator provides the layer of functionality that allows all Java applets to run. Beyond this, there isn’t really anything particularly special about the way Navigator supports embedded Java applets. This simply means that the only significant component in Navigator necessary to support Java is the integrated Java runtime interpreter.

Other than seeing functionality in Web pages that you’ve never seen before, there’s not much in Navigator to inform you that a Java applet is running. A few small things you might notice are the various messages that appear in the Navigator status bar when an applet is preparing to run. You may also notice a significant delay while Java applets are being transferred to your machine, especially those that use a lot of graphics and sound.

Another Java-specific feature of Navigator is located under the Options menu. The Show Java Console menu command causes Navigator to open a Java Output console window. The output window displays output generated by currently running Java applets. Figure 8.2 shows what the Navigator Java Output window looks like.

Figure FIGURE 8.2.

The Netscape Navigator Java Output window.

Configuring Java with Netscape

When you first install Netscape Navigator, Java support is automatically installed and enabled by default. Remember, the Java support in Navigator is built-in, so you don’t have to do anything special to get it working. As a result, you can immediately start viewing and interacting with Java-enhanced Web sites.

The only real Java-specific option in Navigator is whether or not you want Java support enabled. Most of the time you will want to leave Java support enabled, so that you can enjoy the benefits of the Java technology. However, if you are experiencing problems with Java or with a particular Java Web site, you can disable Navigator Java support. To do this, select the Security Preferences command from the Navigator Options menu. The Disable Java checkbox is used to enable/disable Java support. Figure 8.3 shows the Navigator Security Preferences dialog box.

If Java is disabled, you will still be able to view Java-enhanced Web sites, you just won’t be able to view or interact with the Java applets contained within them.

Figure FIGURE 8.3.

The Netscape Navigator Security Preferences dialogue box.

Java Applets

There are already many Java applets available for you to run and try out, ranging from games to educational instruction. Most of them come with source code, so you can use them as references for your own Java programs. Figure 8.4 shows a crossword puzzle Java applet running in Netscape Navigator.

Figure FIGURE 8.4.

A crossword puzzle Java applet running in Netscape Navigator.

The different applications for Java are limitless. Figure 8.5 shows a very interesting application of Java: an instructional dance applet.

Figure FIGURE 8.5.

An instructional dance Java applet running in Netscape Navigator.

If you want to check out some of the Java applet demos, take a look at the Java Applet Demos Web page on Netscape’s Web site, which is shown in Figure 8.6:
Figure FIGURE 8.6.

Netcape's Java Applet Demos Web site.

If you want to find out more about creating your own Java applets that can be integrated into Web pages, check out Part V of this book, “Applet Programming.”


JavaScript is a scripting language described by Netscape as a lightweight version of Java. JavaScript promises to enable less technical Web users and developers the capability to create interactive content for the Web. You can think of JavaScript as a higher level complement to Java. Netscape Navigator supports JavaScript by providing an internal JavaScript interpreter.

JavaScript was designed with the goal of creating a simple and easy-to-use cross-platform scripting language that could connect objects and resources from both HTML and Java. While Java applets are primarily developed by programmers, JavaScript is intended to be used by HTML document authors to dynamically control the interaction and behavior of Web pages. JavaScript is unique in that is has been designed to be complementary to both HTML and Java.

If you can believe it, JavaScript is actually an even newer technology than Java. Because JavaScript was developed jointly by Sun and Netscape, it is almost guaranteed to be widely adopted by the Web community. However, it may still take some time before you see truly compelling applications of JavaScript. Part IX of this book, “JavaScript,” is entirely devoted to understanding and using JavaScript.


The latest release of Netscape’s line of Web products promises to further establish Netscape as the premier Web tool provider. A central technology present in these tools is Java, which brings interactivity to the Web. Netscape Navigator, along with already being the most popular Web browser available, is the first major Web browser to fully support Java.

In this chapter, you learned about the different tools available from Netscape and how Java relates to them. You also learned about JavaScript, and how it is positioned to provide a higher level option to HTML developers wishing to add interactivity without learning Java inside and out. Netscape’s early support for both Java and JavaScript is a sure sign that these technologies are here to stay.

Now that you have an idea about how the most popular Web browser supports Java, you may be interested in learning about a new browser developed by the creators of Java, Sun Microsystems. The next chapter takes a close look at HotJava, Sun’s new Web browser that is tightly integrated with Java.

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