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Interacting with Plugins

The Web is much more than HTML and images. Today, Web sites across the world make use of

many different types of plugins. Plugins give Web browsers the capability to embed small (and

sometimes large) programs or objects into a page without interfering with the underlying HTML.

When a browser encounters content inside of an

element, it hands over rendering

responsibility to the associated plugin.

Originally, the plugin of choice was a Java applet. Applets allowed Web developers to include Java

functionality directly in a Web page. Since that time, many more plugins have been developed.

This chapter focuses on the most popular plugins used today and how you can use JavaScript to

interact with them.

Why Use Plugins?

In the beginning, Web pages were fairly static creations. Before the advent of the DOM, after a page

was loaded its appearance remained the same until it was unloaded. Traditional developers lived in

a world of dynamic interfaces, where everything the user did caused a change on the screen, but

when they turned to the Web, they found the environment severely lacking in dynamism. Then

came Java.

Java originally wasn’t designed for use in Web browsers because, at the time of its inception, the

World Wide Web was nothing but a concept. However, as the Internet and the Web gained popu-

larity, the original Java developers saw the opportunity to enrich the Web browsing experience by

using Java. The result was an experimental browser called HotJava, which was written by Sun

Microsystems as a proof of concept for how Java applets could be embedded into Web pages. For

the first time ever, Web pages were no longer static; instead, there was movement, user interaction

without page reloading, and a bright new future for the Web.

Around the same time, Netscape began developing an architecture for

helper applications

. The basic

idea was to enable the browser to recognize the mime type of information and then launch the

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