This page contains a Javascript interpreter for the esoteric programming language HQ9+. HQ9+ was designed by Cliff L Biffle, who wanted a language where the canonical programs (Hello World, 99 Bottles Of Beer and a quine) were easy to write. The language has four instructions — H, Q, 9 and + — which may occur in either uppercase or lowercase, as shown in the example in the specification. The specification does not define the behaviour of unknown instructions, and this interpreter ignores unknown instructions. The example code below is simply the name of the language.