[SOLVED]How do I detect enter in a text box?

I'm trying to submit a username written in a text input object to a database using ajax, I know how to do this with having the user clicking some kind of submit button but is it possible to detect an enter press when inside a text box?

edit: In case this ever comes up in a search in the future I just did a regular old on enter pressed with the added condition of TextInput.text not equaling ""