How to access repeater items from javascript

<asp:Repeater ID="Repeater1" runat="server">
    <ItemTemplate>
           <script type="text/javascript">
                 function MyFunc() { 
                     $('#box_<%#Eval("ID")%>').slideToggle("500");
                     var ReqFieldValidator = document.getElementById("<%=ReqFieldValidator.ClientID%>");
                     ReqFieldValidator.enabled = false;
                 } 
           </script>

        <asp:CheckBox ID="MyCheckBox_chk" onclick="MyFunc()" runat="server" />

        <div id='box_<%#Eval("ID")%>'>
              <asp:RequiredFieldValidator ID="ReqFieldValidator" runat="server">       </asp:RequiredFieldValidator>
             // Div Content
        </div> 

   </ItemTemplate>
</asp:Repeater>