How to stop UpdatePanel from causing whole page postback

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UpdatePanel

How to stop UpdatePanel from causing whole page postback

<asp:UpdatePanel ID="jp" runat="server" UpdateMode="Conditional" ChildrenAsTriggers="true">
                                             <ContentTemplate>

<asp:Label ID="Label4" runat="server" Text='<%#Eval("inserted_date")%>' />

<asp:Label ID="lblComment" runat="server" Text='<%#Eval("comments") %>'/>

<ul>
                     <li><asp:LinkButton ID="link1" runat="server" CommandArgument='<%#Eval("product_id") %>' CommandName="five_str" OnCommand="fivestar_Command" ForeColor="Green">
                                  4 and 5 star rated certified buyer reviews
                                 </asp:LinkButton></li>
                     <li><asp:LinkButton ID="link2" runat="server" CommandArgument='<%#Eval("product_id") %>' CommandName="three_str" OnCommand="fivestar_Command" ForeColor="Green">
                                  2 and 3 star rated certified buyer reviews
                                 </asp:LinkButton>   </li>
                     <li><asp:LinkButton ID="link3" runat="server" CommandArgument='<%#Eval("product_id") %>' CommandName="thre_str" OnCommand="fivestar_Command" ForeColor="Green">
                                  1 star rated certified buyer reviews
                                 </asp:LinkButton>   </li>
                 </ul>

<asp:Repeater ID="repeat" runat="server" OnItemDataBound="repeat_ItemDataBound" >
<HeaderTemplate>
View all reviews(<%=top_view%>)

<Triggers>

                                             <asp:AsyncPostBackTrigger ControlID ="link1" EventName="Click" />
                                              <asp:AsyncPostBackTrigger ControlID ="link2" EventName="Click" />
                                                <asp:AsyncPostBackTrigger ControlID ="link3" EventName="Click" />

                                          </Triggers>

Whenever I click the button, sure the panel updates - but the whole page posts back like label values also ! I can see the whole page flashing. What the heck am I doing wrong?