JavaScript is a scripting language that was founded by Netscape about a year ago. The language is simple and surprisingly powerful. If you know a more serious programming language (C++ or Java) it has been said that you can master JavaScript in a day. If this is your first language, don't worry. You should still get the concepts quite quickly and, in the process, introduce yourself to many concepts of the more difficult languages.
Currently, MSIE 3.0, and Netscape versions above 2.0 are said to be browsers that read JavaScript. However, since the language is so new, many of these browsers still are refining their ability to interpret the language (Netscape 3.0 being the most dependable). Many times, things that should theoritically work, won't. Don't let this agravate you. Be innovative and look for work-arounds.
JavaScript can be called an object-oriented language. Objects, in real life, are things like your toothbrush. You can hold your toothbrush and interact with it, (hopefully you do). Objects are similiar when you come to talking about programming languages. A JavaScript object, like a text box, is something that you can interact with. JavaScript can interact with a text box by changing the text displayed, or using the entered text for some other purpose.
Scripts, however, are more like cars than toothbrushes. This is because to allow your script to do anything, it takes cooperation between many different objects. Just as in cars, it takes many objects (a steering wheel, tires, an engine, and axles, etc.) to allow your car to go forth.
That's how you can think of object-oriented programming. Practically, object-oriented means that if you write a program, you package code up into units like functions or objects (both which will be defined later). You define these units once, and whenever you need them you just call them. Object-oriented programming is clean, clear, and simple.
To be a good programmer, you must learn to think it terms of objects. It takes practice, and can only be done with practice. However, once you learn to think like this, programming will become extremely easy.
JavaScript has a lot of use for internet programmers. It can make calculations,
validate forms, work with cookies, and detect what browser is being used-- to name a
scarce few. It can, pretty much, carry out most of the functions that previously could
only be done with the more complicated, but, in fairness, probably more secure, CGI
applications. Although JavaScript is so powerful, you don't have to worry about
hackers getting into your system using JavaScript. Likewise, once you start programming
with JavaScript, you shouldn't try anything sneaky. You won't get too far.