Free EcmaScript Interpreter.  A JavaScript interpreter written in Java.

The installation file is approximately 1Mb, it includes the Fesi binary, documentation, source and examples. It will run on JDK 1.4, including the regular expression extension. It should work on all operating systems (however shortcuts are installed on Windows only).

To use regular expression with a version of Java before 1.4, you need to download the required libraries, either the Apache OROMatcher package or the he GNU regular expression package. You do not neet these packages if you have Java 1.4, unless you requires compatibility with previous code.