Original sentence: All non-Mozilla implementations using JavaScript are actually implementing ECMAScript, rather than Javascript.Chrome also implements non-ECMAScript-standard extensions to the language which are present in WebKit, in order to maintain compatability with JavaScriptCore (which is itself based on the KDE KJS library) : V8 JavaScript Engine issue tracker.ECMA-262, edition 5V8, the JavaScript engine created by Google and used in Chrome, implements ECMAScript as specified in ECMA-262, 5th edition: V8 JavaScript Engine.JavaScript 1.8.5"JavaScript" is an ECMAScript varient managed by Mozilla.Typically, "JavaScript" support by refers to support for ECMA-262, edition 3, though some - notably Chrome, but also Opera 12 and Internet Explorer 10 - target ECMA-262, edition 5
Edited sentence: ECMA-262, edition 5V8 implements ECMAScript as specified in ECMA-262, 5th edition: V8 JavaScript Engine.JavaScript 1.8.5Mozilla manages the official version of JavaScript.Most non-Mozilla implementations claiming JavaScript "compliance" do not actually support most JavaScript extensions; rather, they target ECMA-262, edition 3