You will need to take some care to avoid derailing your users on version differences. Since JavaScript 1.0 was introduced with Netscape 2.0, it has undergone many changes. The current version of JavaScript (for Netscape 4.0x) is 1.2.

In addition, Microsoft has produced its own implementation of JavaScript called JScript, and it has also undergone revisions (the current version, for IE 4.0, is 3.0).

As with much of the best web technologies, then, developers are faced here with the task of testing their scripts on as many browsers and platforms as possible. And this testing can be especially tedious, since debugging tools for JavaScript leave much to be desired.

There is some hope for better times ahead....The ECMA standards organization has released a general specification for ECMAScript, a general scripting language derived from JavaScript. Microsoft claims that JScript is a fully compliant implementation of ECMAScript, while Netscape's JavaScript 1.2 is not, and that when it becomes so, ECMAScript incompatibilities will be no more. Netscape's take, as you will have guessed, is slightly different. I won't dwell on the details, but just urge all developers to seize every opportunity to let both corporations know that you want your stuff to work on both browsers, and that you're not interested in who is at fault, just in compatibility.