Checkbox doesn't fire ValueChanged after Clicked

I’m trying to execute a code within an event ValueChanged, in a checkbox.

The event is not triggered when the state of the checkbox changes (by clicking), but if I click any button on the screen, the checbox event occurs as if stacked on the client side.

This is a bug or is expected behavior.

Add below to your code.


Dear Sir,
I have some problem regarding the ValueChaneEvent,

Basically have OptionGroup of Checkbox having multipleSelection true.
I want when I select the “Colleges” CheckBox,a DropDown List of College name should appear on same window;
Note- My Option Group has three Checkbox ie.(“Colleges”,“ACT”,“Fastweb”) which are fetched from database.
I have attached the code section.
Please help me ass soon as possible.

Thanks a lot