Java is a computer programming language. It was developed by Sun Computers. It is derived from another language, C++. Its significance to the Internet is that it has been adopted as a language which can be run by a browser. That is a program written in Java can be downloaded by a web browser, and run by the browser. This enables programmers to do things on your browser which plain old HTML cannot. This is possible because a Java program is platform-independent, that is it can, in principle, be run on any make of computer. This is possible because Java is an interpreted language, and all that is needed on the client system is the Java Virtual Machine. This is a program which is not platform independent, and so has to be written for each client system, but which is simpler to write. It's job is to interpret and run, Java programs. Because of the interpreted nature of Java, it is possible to impose a security cordon around Java programs, and prevent them from doing malicious things to client systems. Thus making Java safe for use on the Internet. and JavaScript? JavaScript has been described as Java-Lite. It is simpler than Java, but is more limited and is constrained by what can be done with HTML. JavaScript programs are embedded as text within normal HTML files.