Check out this table: http://en.wikipedia.org/wiki/ECMAScript#Version_correspondence http://en.wikipedia.org/wiki/ECMAScript#Version_corresponden... I think th

Check out this table: http://en.wikipedia.org/wiki/ECMAScript#Version_correspondence http://en.wikipedia.org/wiki/ECMAScript#Version_corresponden... I think the 1.# versions came from Mozilla, but the ES editions are the true standards. So 1.7 is ES3 plus some extensions in Firefox. It looks like ES6, when finished, will be 2.0.