Java allows programmers to make small applications, called applets, which get downloaded along with a web page.
These can be anything from games and interactive maps to currency converters or sound players.
The downside of these applets is that they can take a little time to download and because they are so flexible can be used in harmful ways.
Internet Explorer for Windows
Go to the Tools menu in IE and choose Internet Options.
Next click the Security tab.
Make sure the Internet Zone is highlighted and press the Custom Level button to open the security options.
Internet Explorer for Mac
Find the Preferences option on the Explorer menu. Select the Web Content bullet from the list on the left hand side of the window.
Find the Active Content section. Make sure that the checkbox next to Enable Scripting is checked.
To enable Java, click the Java link in the Web Content section.
Safari for Mac
In Safari, go to the Safari menu and choose Preferences.
Click the Security tab.
Firefox users should go to the Tools menu and select Options.
Java, on the other hand, is a program which you may have to download if you use a PC. Apple Mac owners will have this already as part of OS X.
Click the step-by-step guide below if you need to get Java for Windows.