This page contains a Javascript interpreter for the esoteric programming language HQ9++. HQ9++ was designed by David Morgan-Mar, who wanted to produce a backwards-compatible object-oriented extension to HQ9+. The new ++ instruction increments the accumulator twice, and instantiates a new object. The specification does not define whether, for example, +++ should be interpreted as two instances of ++ or just one, and this interpreter interprets +++ as containing one instance of ++. As with the HQ9+ interpreter, this interpreter ignores unknown instructions.