Hi gowthamtr,

That will depende on how the specific browser you're using implements the back funcionality.

Anyway, if you use javascript to create or change options in forms, you should not use the back button, but a button implemented by you, that will reinitiate the selects to the last selected values.

You can't relay on any default browser behaviour as diferent browsers and even diferent versions of the same browser, or even diferent plugins on the same version of the same browser will work in diferent ways.