By: John Michael Pierobon
Every day more and more Web pages appear to be "interactive" in that portions of the screen change colors when you move your mouse over a button or warnings pop up when you fill out a form improperly. This interactivity is achieved with JavaScript.
JavaScript is a platform-independent scripting language developed by Netscape for use in Web pages. Originally, Netscape was working on a scripting language called LiveScript, but with help and hype from Sun Microsystems, transformed the language into JavaScript.
JavaScript is not Java. There is no direct relation between JavaScript and Java. Java is a cross-platform programming language that can be used to write little, stand alone applications known as "applets" that can be embedded into Web pages. JavaScript is structured in ways that are somewhat similar to Java, but there are many differences between the two.
For example, JavaScript cannot run independently, whereas Java can. JavaScript is not a scaled down version of Java with some of the features left out, although it may seem that way to the novice.
JavaScript more closely resembles VBScript. VBScript is a subset of Microsoft's Visual Basic language. There are many differences between JavaScript and VBScript. Scripts written in the two different scripting languages are not interchangeable, except in very rare and simple cases. VBScript is presently supported only by Microsoft's Internet Explorer whereas JavaScript is supported by both Internet Explorer and Navigator.
Microsoft has implemented its own version of JavaScript. They call it JScript.
JavaScript is safe. JavaScript has many limitations which keep it from causing harm to your computer. The most significant is that JavaScript works entirely within the browser. JavaScript can only access those objects which the browser currently stores in the computer's dynamic memory. It cannot directly write information to any file on the user's computer (except to a cookie file).
JavaScript cannot manipulate any peripheral devices. JavaScript cannot manipulate or access any program aside from the browser. You need not fear that JavaScript will damage your software, data, or computer in any way. The worst JavaScript can do is produce an annoying error message if it does not run properly.