Once the user submits the form, the form should still be displayed with selected options and not go to thank you page.
In other word just like updating the form fields.
thank you. But whatever I came across, on Success the form is hidden and thank you message appears. I am familiar with that behavior, but what I want is
#1 interaction form display - enter your first name; enter your last name - click on submit button
#2 on submit the form is displayed again with first name and second name, but with message your info has been updated.
if I remove form.getFormElem().hide(); the submit become deactivated with text please wait.
So don't hide/replace the entire form.
Replace only the button row (.mktoButtonRow) with your "has been updated" message.