JavaScript, was originally named Mocha, later it was renamed to LiveScript, and then to JavaScript.
The LiveScript to JavaScript name change came because Netscape and Sun did a license agreement.
The language was then submitted for standarization to the ECMA International Organization. By that time, Netscape didn't allow the use of the "JavaScript" name, so the standarized language is named ECMAScript.
JavaScript isn't actually an open name. Now it's a trademark of Sun (now Oracle).
There still a lot of confusion, some people still think that JavaScript, JScript, and ECMAScript are three different languages.
ECMAScript is the "standards" name for the language.
JavaScript is technically a "dialect" of ECMAScript, the Mozilla Foundation can use "JavaScript" as the name of their implementations (currently present on the Rhino and SpiderMonkey engines).
In the early days, Microsoft decided also to do what Netscape was doing on their own browser, and they developed JScript, which is also an ECMAScript dialect, but was named in this way to avoid trademark issues.
