How to get a Child Web Form as MODEL window?

[Rupang]

1. How to get a Child Web Form (MODEL Window where user
must take an action on that to go back to the Parent
window) from a Parent Web Form?

2. How to pass a parameter between Child and Parent Web
Forms?

Example of the scenario:

I've two webforms webform1 and webform2 with code behind
in C#.

In webform1, Let us say I've an event which triggers from
nth line of the statement; from there I should able to
call a child window/Webform2. In that child window I will
have a checkbox/optionbutton. After closing the child
window, now I should able to capture in the (n+1)th
statement of the event
in the WebForm1 that whether checkbox/optionbutton is
selected in childwindow or not.

Thanks,
Rupang