Flutter Web submit form on enter key

 For a TextFormField the property to handle this would be onFieldSubmitted. You can copy the code from your onPressed of the RaiseButton to this. For e.g.

onFieldSubmitted: (value) {
                if (_formKey.currentState.validate()) {
                  _formKey.currentState.save();
//               var result = await auth.sendPasswordResetEmail(_email);
//               print(result);
                  print(_email);
                  Navigator.of(context).pop();
                }
              },