Our focus is sufficiently interoperable ECMAScript. More formally, it is the intersection of all ECMAScript dialects relevant to a given context, i.e. the set of all ECMAScript programs which cause no errors (or other problems) in any of the parsers for said dialects.
The most common context is the World Wide Web, specifically the traditional or "non-mobile" portion. In the absence of contributors concerned with other contexts, this wiki will ignore them. However, templates and categories to indicate any given article's context shall be enthusiastically created upon the arrival of such contributors. (Note that Flash and ActionScript have their own wiki.)