What are 'plug-ins'?
Plug-ins are small computer bits of software that let you view a document, interact with an image, listen to music or watch a video.
If you did not have the right plug-in on your computer, you would not be able to listen to your favourite song or see animations and video on screen.
So, if you want to play a game that uses Shockwave and you don't have it on your computer you'll be prompted to install it.
Getting plug-ins
They are called plug-ins because they 'plug in' to your browser the first time you download them onto your computer, generally installing automatically.
When you go to a site that needs a plug-in your browser will automatically know and ask you whether you want to download the plug-in needed.
After that they start themselves whenever they are required - that is, whenever you visit a website designed to be viewed using a particular plug-in.
Typically, plug-ins add 'multimedia' functions which enable you to receive information in more powerful ways than the normal text and image - such as animation, sound or video.
Why plug-ins?
You may wonder why plug-ins are needed at all and why the main browser types don't automatically include every type of functionality as standard?
The answer is that this would simply not be practical. There are hundreds of plug-ins - with new ones created all the time - and a basic package could never include them all and be up-to-date.
Plus, it makes more sense to keep the basic browser as small a possible to make it easier to install and then leave it up to individual users to decide what extra functionality they require.
How do you get them
Use these WebWise Step-by-Step guides to help you download popular plug-ins:
| Plug-in | What it does |
| Real Player | Popular sound and video player - used on BBCi |
| Flash Player | Used for animations and games |
| Shockwave Player | Used for 3d animations and games |
| Cortona | Used for viewing and interacting with virtual environments |
| Acrobat | The reader is needed to look at PDF files |
| QuickTime | QuickTime - often used for high quality video (preferred on Macs) |
| Windows Media Player | Microsoft's media player - plays sound and video |
| iPIX | Used for viewing 3D Picture Bubbles |
Once installed, often you will have to restart your browser or even your operating system to make a plug-in active.
Generally plug-ins will be free but occasionally a company will ask for a fee for a more sophisticated version.
As a casual individual user you should never need to buy these jazzy versions: the free versions will do everything you want.
Finally, a tip: if you get bored waiting for big files to download over your creaky modem at home or are worried about the size of your phone bill, try looking through the internet magazines in your local newsagents.
Most of them have cover-mounted CD-Roms carrying up-to-date versions of all the most used plug-ins, so for a couple of quid you can install them in an instant, and swap your free disks with you friends!