Jiffo ("Javascript Interactive Fiction Framework that's Open Source Software") is a framework for creating parser-based interactive fiction (IF) games/stories that is open source software (OSS) and built on Javascript.
It's designed to be easy to get started with and use. It is released under the MIT license, so there are basically no restrictions on reuse or modification. Since it's in Javascript you can easily and directly use all of Javascript's capabilities, libraries, and so on.
For more information, see the tutorial in file tutorial.md. You can also see the sample game catch that cat.