在JavaScript中与PHP的mcrypt匹配的AES

Is there any JavaScript libs that lets you encrypt and decrypt 256 bit AES the way you do it with mcrypt in PHP (and get the same result of course)? I want to give it a variable-length message and a 32 chars key. All libs I find wants fixed-length blocks of cleartext and byte-arrays of keys.Is there any JavaScript libs that lets you encr