<script type="text/javascript">
    function SlideUp() {
        $('.sectionPanel').slideUp("slow", function () { return true; });
    }
    </script>

    <asp:LinkButton runat="server"  CssClass="sideTab" OnClientClick="return SlideUp();" OnClick="SideMenuTab_OnClick" >Breach Details</asp:LinkButton>
    <asp:LinkButton runat="server" CssClass="sideTab"  OnClick="SideMenuTab_OnClick" OnClientClick="return SlideUp();">Additional</asp:LinkButton>

<asp:Panel runat="server" ID="uxPanel1" CssClass="sectionPanel" style="background-color:Yellow;">
Panel 1
</asp:Panel>
<asp:Panel runat="server" ID="uxPanel2" CssClass="sectionPanel" style="background-color: Red;">
Panel 2
</asp:Panel>