In event name of ur update panel u have written "Click" as event but in ur linkbutton control onclick event value is "lnk1_Click". If u r writing ur code in ASP.Net then Handler in the event like Protected Sub lnk1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles lnk1.Click And remove the event name in the Code onclick="lnk1_Click" from ur html and try then. Best of Luck. Regards, Smart Boy Mumbai, (INDIA)