Spidermonkey is a standalone javascript/ecmascript interpreter. it can either take input from files or from a command line driven interface.

ecmascript (ecma-262) is a dynamic scripting language supporting prototype based object construction. the basic syntax is intentionally similar to both java and c++ to reduce the number of new concepts required to learn the language. language constructs, such as if statements, for and while loops, and switch and try ... catch blocks function the same as these languages (or nearly so).

javascript is a superset of the ecma-262 edition 3 (ecmascript) standard first introduced by netscape and now led by the mozilla project.