Plugins/Active X
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Plug-ins and Active X Controls

Have you ever visited a Web site, only to be told that you were missing a plug-in necessary to view a specific element of the page? If so, you will be happy to know that this week we are going to learn how to download plug-ins as well as standalone applications.

Plug-ins exist to fill the gap left behind by traditional Web browsers that are only able to display text, images, audio and video. Well….the audio and video support offered by browsers are limited in that they cannot play an audio or video file until the entire file has downloaded. Netscape intrinsically supports Plug-ins. Internet Explorer does not.

The following is Webopedia.com's definition of a plug-in:

A hardware or software module that adds a specific feature or service to a larger system. For example, there are number of plug-ins for the Netscape Navigator browser that enable it to display different types of audio or video messages. Navigator plug-ins are based on MIME file types.

With plug-ins you can listen to live audio and video news broadcasts and radio/talk shows. In addition, you can listen to live and taped concerts, sporting events, and radio stations from around the world. You can also play games right from the confines of your Web browser. As you can see, plug-ins take the Web experience to a higher level. They do this by utilizing a buffer. The programs hold enough of the file in a buffer so that if the connection slows down, there is still enough time to have the content retransmitted before the listener hears a "break in the action."

Each time you start your browser, it checks your computer to see which plug-ins you have installed. As you move from one site to another, your browser will encounter links that refer to files that require plug-ins. For example, if you click on a link with the extension .mov, the QuickTime plug-in will start.

The following Web site will let you know what plug-ins you have installed in your browser. This page is only useful if you are running Netscape. However, figure 9-1 on page 9.04 shows what a typical page will look like if a required plug-in is missing. The site will generally offer a link to the company that created the plug-in. The company's site is where you can easily download and install the plug-in.

When you upgrade your browser, you sometimes lose many or all of the existing plug-ins, so you may have to download them again. On the opposite end of the coin, downloading and installing a new browser version may result in you having access to plug-ins that you had never downloaded before.

Plug-ins work in three different ways.

  • They may take up a portion of your screen
  • They may take up the entire browser window
  • They are hidden from your view

The best thing about plug-ins is that they work without you having to learn any special commands or codes. If you visit a Web-page that requires a plug-in to be viewed correctly, the browser will launch the plug-in if it is installed/embedded in the browser.

You install a plug-in the same way you would install a file. During the installation process, the plug-in’s set up program will search your hard drive for Web browsers. When it finds Netscape, it will install by embedding itself inside the browser.

Some of the more popular plug-ins include

  • The Real Player—Plays audio and video files as they download
  • Shockwave—Displays entertaining rich-media Web content.
  • Shockwave Flash displays high-impact, animated Web content.
  • Quick Time—Apple’s format for streaming video (Watch as it downloads)
  • Adobe Acrobat Reader—View files exactly as the author intended them to be viewed. You can visit the U.S. Government’s site and download tax forms in .pdf format.

More plug-ins can be found at:

Helper Applications

A helper application differs from a plug-in in that the helper app. is not embedded into the browser. Instead, when the browser needs the program to display content, it will find the program on the hard drive and start it. Therefore, helper applications are available for you to use when you are not on the Web.

Many plug-ins are also available as helper applications, in fact most plug-ins began as helper apps. If you have a choice between downloading one or the other, ask yourself if you will ever need to use the program while you are online. If the answer is yes, download the helper application. If the answer is no, download the plug-in.

You might be wondering how a browser knows what helper application should be loaded as a file is downloading. Located in every file’s header is its MIME type. This tells the browser what type of program it is, along with the file’s extension. During installation, helper applications may automatically configure the browser to call on them when they are needed.

You will know fairly quickly when there is no helper application available to handle a specific MIME type. When this is the case, as soon as the host’s server sends back the MIME type to the browser, the browser will flash you a message telling you that it does not know how to handle the type of file that is about to be sent. You can choose to download the file anyway or cancel the request.

Some popular helper applications include:

Internet Explorer uses Active X controls, not plug-ins. ActiveX controls are small programs used by many Web sites to download and execute special commands on users' computers. Once installed, the controls can be reused by many applications.

 There are less Active X controls available than plug-ins. However, the great things about Active X controls is that they install themselves. You don't have to worry about where you save the controls on the hard drive. However, there are security issues regarding Active X controls.

Active X controls'  security feature is a technology called Authenticode, which requires that all ActiveX controls be digitally signed by their authors. So if you ever install a questionable control, you'll know exactly who is responsible.