set all check boxes inside page to false

I could have any number of checkboxes in my table.

<input type="checkbox" value='<%#Eval("MapID") %>' class="chk" runat="server"/>...

So how do I set all the checkboxes to false from code behind?

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

        <ContentTemplate>

            <asp:ListView ID="lvCurrentMaps" runat="server"  >
            <LayoutTemplate>


                <table cellpadding="0" cellspacing="0" border="0" class="display rndCorner2" id="example" width="100%">
                 <thead>
                    <tr id="Tr1" runat="server" class="itemTableHeader">
                        <td>
                        <asp:Label runat="server" ID="Label1" Text="Select" />
                        </td>
                        <td id="Td1" runat="server">
                            <asp:Label runat="server" ID="lblMapID" Text="Map ID" />
                        </td>
                    </tr>
            </thead>
            <tbody>
                    <tr id="itemPlaceholder" runat="server">
                    </tr>
               </tbody>
                </table>


            </LayoutTemplate>
            <ItemTemplate>
                <tr id="Tr2" runat="server" class="itemTableData">
                    <td id="Td6" runat="server"  class="chkbox">
                        <input type="checkbox" value='<%#Eval("MapID") %>' class="chk" runat="server"/>
                    </td>
                    <td id="Td1" runat="server" onclick='<%#"doPostBackForView("+Eval("MapID")+")" %>' style="cursor:pointer !important">
                        <asp:Label runat="server" ID="lblIDMapValue" Text= '<%#Eval("MapID") %>' />
                    </td>
                </tr>
            </ItemTemplate>
            <AlternatingItemTemplate>
                <tr id="Tr2" runat="server" class="altItemTableData">
                    <td id="Td6" runat="server"  class="chkbox">
                        <input id="Checkbox" type="checkbox" value='<%#Eval("MapID") %>' class="chk" runat="server"/>
                    </td>
                    <td id="Td1" runat="server" onclick='<%#"doPostBackForView("+Eval("MapID")+")" %>' style="cursor:pointer !important">
                        <asp:Label runat="server" ID="lblIDMapValue" Text= '<%#Eval("MapID") %>' />
                    </td>
                    <td id="Td8" runat="server" onclick='<%#"doPostBackForView("+Eval("MapID")+")" %>' style="cursor:pointer !important">
                        <asp:Label runat="server" ID="lblMapNameValue" Text= '<%#Eval("MapName") %>' />
                    </td>
                    <td id="Td9" runat="server" onclick='<%#"doPostBackForView("+Eval("MapID")+")" %>' style="cursor:pointer !important">
                        <asp:Label runat="server" ID="lblMapDescValue" Text= '<%#Eval("MapDesc") %>' />
                    </td>
                </tr>
            </AlternatingItemTemplate>

        </asp:ListView>                   
        </ContentTemplate>
        </asp:UpdatePanel>

I was trying something like:

foreach(var li in lvCurrentMaps.Items)
        {
            li.DataItem = false;
        }

        AccesUpdatePanel.Update();

any ideas? possibly through a ScriptManager?