ajax

i have registration form which i put inside update panel of ajax 

works fine no problem

but in this form i have 2 dropdown controls country and state,if i select coutry
as usa then state dropdown will show usa states 

works fine no problem here also

but when i select a country it causes post back now if i submit button the
validators doesnot popup

when i remove update panel then if i repeat the above thing then the validators
will pop up

what is the solution.

It might be related to what's discussed in this post:
http://blogs.msdn.com/mattgi/archive/2007/01/23/asp-net-ajax-validators.aspx

You need to follow the instructions, i.e. download the Validators.dll from the
zip file here, add it to the bin folder of your project then copy the tagMapping
section into your web.config file. Since I don't know much more about your
problem I can't be sure this is the solution but it might help.