I'm pretty sure if you did it on line they recieved it and looked it over now all you have to do is play the waiting game and see if they contact you for an interview. good luck :)
Hello, this is (name). I'm just calling to confirm that you've received the application I submitted online. (usually, they take it from here).
Sending an email, be polite though, is usually the way to do it.
just call and ask