Duktape is easy to integrate into a C/C++ project: add duktape.c and duktape.h to your build, and use the Duktape API to call Ecmascript functions from C code and vice versa.
Embeddable, portable, compact
Ecmascript E5/E5.1 compliant
Built-in regular expression engine
Built-in Unicode support
Minimal platform dependencies
Combined reference counting and mark-and-sweep garbage collection with finalization
See duktape.org for packaged end-user downloads and documentation. The end user downloads are also available from the duktape-releases repo as both binaries and in unpacked form as git tags.