Java vs. JavaScript

These two technologies don't have a lot to do with each other.

While they apparently have some syntax elements in common, and historical antecedents, Java is a full programming language from Sun Microsystems; JavaScript is a simplified scripting language. JavaScript didn't have Java in its name until the last minute before the first version was released, the result of a marketing deal between Sun and Netscape.¹

Java http://en.wikipedia.org/wiki/Java_%28Sun%29

Java Programming Language http://en.wikipedia.org/wiki/Java_programming_language

Including history

Java Runtime Environment http://en.wikipedia.org/wiki/Java_Runtime_Environment

Java developers' home page http://java.sun.com/

JavaScript http://en.wikipedia.org/wiki/JavaScript

JavaScript home page http://www.mozilla.org/js/

Java is supposed to be a great boon for programmers, a "write once, run anywhere" system. To execute Java code, a PC must have a Java Runtime Environment (JRE) installed and enabled. The idea is that all platforms are supposed to have a Java Runtime available, and Sun does make JREs available for free download for different systems. Microsoft Windows XP, Mac OS X, and most Linux distributions include native Java support.

Any modern Web browser can execute JavaScript on its own.²

If you see a working calculator³ in the table in the right margin, then your PC has a JRE installed and Java is enabled. If there are no calculator buttons, check your Control Panel: if there's a Java item, then it would appear you have a JRE installed but it's disabled. You can enable it from Preferences in your Web browser, where you should find a check box for JavaScript also. If you have a JRE installed it should also appear in the list of programs at Control Panel, Add/Remove Programs ("J2SE Runtime Environment").

JavaScript is most widely seen used in Web publishing, although it does have other possible applications. Java is less commonly seen, and is used for applets on Web pages as here, occasionally for Website navigation, and for non-Internet software, such as certain extras features of the open-source freeware office suite OpenOffice.org (see also my OpenOffice.org pages on this site).

Use of Java applets on Web pages is controversial, and is considered a bleeding-edge annoyance in some circles. By me, for example; the one on this page, presented for diagnostic purposes, is the only Java applet on this site.

1. At the time Netscape was getting ready to release what became JavaScript 1.0 (then called LiveScript) a lot of pundits were saying Sun Java was going to be the Next Big Thing, and the idea of the marketing name deal was to ride Java's coattails. It turned out Java mostly stagnated except for server-side stuff (and Sun projects) while JavaScript flourished like dandelions. Now the similarity in names mostly just confuses people; a Dilbert scenario if there ever was one.
2. If the text in the second cell in the table in the right margin of this page says "JavaScript is disabled" then somebody has turned off the JavaScript support in your Web browser, possibly as a clumsy way to suppress popup windows. Having JavaScript disabled will break navigation features and other features of many Web sites; more than 99% of this site's users have JavaScript enabled. If the title bar of your browser says "Internet Explorer" you can get much better popup blocking without turning off JavaScript by switching to Mozilla Firefox; see my Web browsers page for more.
3. Calculator applet found at Java Boutique, author Koen de Vries.

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