It's not AES but tweetnacl.js, which is a port of the C tweetnacl, which is itself a port of NaCl for embedded systems, has good encryption for embedded systems. I've used the C version of tweetnacl on a Pebble to do encryption/decryption.
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
It's not AES but tweetnacl.js, which is a port of the C tweetnacl, which is itself a port of NaCl for embedded systems, has good encryption for embedded systems. I've used the C version of tweetnacl on a Pebble to do encryption/decryption.