'add a button then give it a new onclick attribute like you would in javascript.



Private Sub Page_Load(ByVal sender As System.Object, _
                      ByVal e As System.EventArgs) Handles MyBase.Load
   If (Not Page.IsPostBack) Then
      Me.BtnDelete.Attributes.Add("onclick", _
                   "return confirm('Are you sure you want to delete?');")
   End If
End Sub