crypto.js

var crypto = require("crypto");

var repeat = function(str, times){
    var _str = str;
    while(--times){
        str += _str;
    }
    return str;
};

var cipher = crypto.createCipher("aes-128-ecb", repeat("1", 16));
// changing to "ascii" or "binary" will give the same result
console.log(cipher.update(repeat("2", 16), "utf8", "base64")); // prints K5GLLZeXr3ufthAEFTTe

crypto.py

import base64
from Crypto.Cipher import AES

cypher = AES.new("1" * 16)
print base64.b64encode(cypher.encrypt("2" * 16)) # prints MoiphN0G/1jpOWCx3sUPHg==

crypto.rb

require 'openssl'
require 'base64'

c = OpenSSL::Cipher::Cipher.new("aes-128-ecb")
c.encrypt
c.key = "1" * 16 
e = c.update("2" * 16)
e = Base64.encode64(e)
puts e # prints MoiphN0G/1jpOWCx3sUPHg==