@seanlinsley only to add one thing. Setting this as form applies working submission of form on return key and working in other devices than pc browser and acting as form. So all other ways to submit form are working also. (if they are using something other than enter key). Also to consider is supporting devices using accessibility features of browser. To note:
http://tjvantoll.com/2013/01/01/enter-should-submit-forms-stop-messing-with-that/
to quote:
  
    However, much like implicit submission, surrounding form data with a true <form> tag is vital for accessibility. Most screen readers have a mode specifically for filling out forms, and by omitting a true <form> tag you risk this mode not being activated.