Developing a Loading Bar after Confirm Dialog Click

Hi All,

I am developing a utility and facing an issue.
The following describes what i intend to achieve:

1. User will click on "Submit"Button.
2. User will be prompted a confirm dialog box.
3. On "No" , it will return.
4. "Yes" click will take it to a method which does some processing.
5. As processing can take sometime, i want to show loading bar after user clicks "Yes" in confirm dialog box.
6. However, When i click "Yes"; the dialog box remains there and i can't see th progress bar.

Request you to please help me with this.