Call Server Side Event from Javascript

     In my Application I am using ModalPopupExtender for Popup window. In Popup window I display one Gridview. Now on RowDataBound Event of that GridView, I have added one LinkButton to one of the column. 

    Now I want to open another Popup window on the Click of LinkButton which I have added in the GridView and want to display another GridView Depending on values of first Grid View. 

   But LinkButton_Click() Event is not firing.

I tried using Javascript by using __dopostback() same issue my server side event for link button not firing..

Any Help Appreciated......

Thanks,

 Vikram