What is JavaScript?

JavaScript is an interpreted language that is used to provide some interactive functionality to web pages. The language was originally called Livescript but the name was changed to attempt to cash in on the popularity of Java (which is a totally different language).

JavaScript was originally introduced in Netscape 2. While attempts have been made to develop other languages to run inside the browser itself, none of the others hasbeen supported by more than one browser. Microsoft introduced two languages - vbScript and jScript - in IE3 with jScript being close enough to JavaScript that you can treat it as the same language and just use feature sensing to handle the differences. With IE9 introducing true JavaScript support all popular browsers now support JavaScript

In order to ensure that ball browsers could support the same JavaScript language rather than each having to produce their own proprietary variant, Netscape passed control of the Javascript language to the ECMA standards body and so the core standard for the language was renamed to ECMAScript. After much disagreement on the future direction of the language beyond ECMAScript 3 with some browsers backing ECMAScript 3.1 and others backing EXMAScript 4 they reached agreement in 2011 with the new version of the standard being called ECMAScript 5.

JavaScript now is a far different language to what Netscape originally introduced and while there is still no standard for interacting with the browser there is a standard for how JavaScript sgould interact with the web page with Netscape 4 and Internet Explorer 4 being the last popular browser that didn't support it (they introduced competing proprietary alternatives).Since then the way JavaScript can be coded has changed significantly with it now being possible for a web page to contain several completely independent scripts that can interact with the same elements within the page without interfering with one another with just one or two script tags at the bottom of the web page to link the scripts into the page. The days of having to hard code JavaScript into the HTML disappeared with Netscape 3 (although there are still many scripts around that are more appropriate for that browser than they are for modern ones).

For a full series of tutorials by example on how JavaScript should be written for modern browsers see javascriptexample.net.


This article written by Stephen Chapman, Felgall Pty Ltd.

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