The UpdatePanel control updates a portion of a page without updating the entire page. <%@ Page Language="C#" %>"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> UpdatePanel Simple Page Time: <%= DateTime.Now.ToString("T") %> id="up1" runat="server"> UpdatePanel Time: <%= DateTime.Now.ToString("T") %> id="btn" Text="Update" runat="server" />