use runat="server" in the div element.
<div id="dvFirstDiv" runat="server" style="display: none;>
SOme text in the first div
<div>>
You can access this div id in the code behind file to take the inner html of the Div Element.
string innerText = dvFirstDiv.InnerText;
string InnerHtml = dvFirstDiv.InnerHtml;
I hope this is what you are pointing out. If it is not I am sorry.