how to save div innerhtml back to database

i have a user control used to display dyanmic web content. when I return the web content from database,  I assign it to div innerhtml. i also set div contenteditable="true", so admin can edit the content in the browser. well the problem is after the editing, I am not able to read the new div content from the code bebhind. although I can read it from the javascript. but i need to save the new content back to the database. could anyone help me? thanks!

here is what i have

<input type="hidden" id="hidvalue" name="hidvalue" runat="server" />
<asp:Button ID="cmdSave" runat="server" Text="Save" onclick="cmdSave_Click" />
<div id="divcont" runat="server" contenteditable="true">
</div>



protected void Page_Load(object sender, EventArgs e)
{
cmdSave.Attributes.Add("onClick", & ...