Thanks for responding and support.
FYI : I have added OnChange method in first dropdown and defined the method in javascript which get called appropialy onchange. Now when the value get change in first dropdown , we get the selected value in javascript method , now I want to pass this value in perl method to retrive 2nd dropdwon value . but her I am unable to call the perl method from javascript/ Ajax .
Please help me how to call perl method from javascript/Ajax ?