I need to set one background color to div in repeater control

Hi All,
I need to set one backfround color  to div  (Id= divsubtopic)  on click of Linkbutton (ID =Linkbutton1). How I could solve this problem.
<asp:Repeater ID="reSubtopic" runat="server"> <HeaderTemplate> <div class="main" > <div class="inner"> </HeaderTemplate> <ItemTemplate> <asp:LinkButton CssClass="metro-tile-link" ID="LinkButton1" runat="server" CommandArgument='<%# DataBinder.Eval(Container.DataItem, "sub_id") %>' OnClick="LinkButton_Click" OnClientClick="return LinkButtonClick(this);" > ...