jordan says:
<
div
id
=
"product"
runat
=
"server"
>
</
div
>
you need to place above div outside the menu div like below
<div id="menu">
<ul class="nav navbar-nav navbar-left">
<li class="active">
<asp:LinkButton ID="lnkAllProducts" CssClass="btn btn-block" Text="All Products"
runat="server" OnClick="BindImages" />
</li>
<li>
<asp:LinkButton ID="lnkBestSellers" CssClass="btn btn-block" Text="Best Sellers"
runat="server" />
</li>
<li>
<asp:LinkButton ID="lnkNewestAdded" CssClass="btn btn-block" Text="Newest Added"
runat="server" />
</li>
</ul>
</div>
<br />
<br />
<br />
<div id="product" runat="server">
</div>