Substitution.aspx font size:
<%@ outputcache duration=120 varybyparam="none" %>

<html>
<head>
<title>Substitution Control Example</title>
<link rel="stylesheet" href="/shared/netdemos.css">

<script language="C#" runat="server">

   void Page_Load ( object src, System.EventArgs e ) {
      // display the current date and time in the label.
      // output caching applies to this section of the page.
      cachedContent.Text = DateTime.Now.ToString ( );  
   }

   // the Substitution control calls this method to retrieve the current date and time. 
   // this section of the page is exempt from output caching. 
   public static string getCurrentDateTime ( HttpContext context ) {
      return DateTime.Now.ToString ( );
   }

</script>
</head>

<body>
<!-- #include virtual="~/shared/top.inc -->
<div class="header"><h2>Substitution Control Example</h2></div>

<!-- #include virtual="~/shared/viewsrc_top.inc" -->
<hr size=1 width=92%>

<div align="center">
<form runat="server">

   <p>This section of the page is cached</p>
   
   <asp:label id="cachedContent" runat="Server" />

   <p>This section of the page is exempt from output caching</p>

   <p id="msg"><asp:substitution id="subContent"
      methodname="getCurrentDateTime"
      runat="Server" /></p>
   
   <p><asp:button id="RefreshButton"
      text="Refresh Page"
      runat="Server" /></p>

</form>
</div>

<hr size=1 width=92%>
<!-- #include virtual="~/shared/viewsrc.inc" -->

</body>
</html>