WebControlStyle.aspx font size:
<html>
<head>
<title>Dynamically Setting the Style Properties of a Web Control</title>
<link rel="stylesheet" href="/shared/netdemos.css">

<style>
   #greeting {padding:10}
</style>

<script language="C#" runat="server">
void applyStyle ( Object src, EventArgs e ) {
   switch ( myStyle.SelectedIndex ) {
      case 0:
         greeting.Style [ "font" ] ="bold italic 13pt verdana";
         break;
      case 1:
         greeting.Style [ "color" ] ="maroon";
         break;
      case 2:
         greeting.Style [ "background-color" ] ="khaki";
         break;
      case 3:
         greeting.Style [ "border" ] ="1px silver inset";
         break;
   }
}

void resetStyle ( Object src, EventArgs e ) {
   greeting.Style [ "font" ] ="";
   greeting.Style [ "color" ] ="";
   greeting.Style [ "background-color" ] ="";
   greeting.Style [ "border" ] ="";
}
</script>
</head>

<body>
<!-- #include virtual="~/shared/top.inc" -->
<div class="header"><h2>Dynamically Setting the Style Properties of a Web Control</h2></div>

<hr size=1 width=92%>

<div align="center">
<form runat="server">
   <p><b><asp:label id="greeting" runat="server" text="Greetings, earthling, welcome to ASP.NET." /></b>

   <p>&nbsp;</p>

   <p>Choose style to apply: <asp:dropdownlist id="myStyle" runat="server">
      <asp:listitem text="Font" />
      <asp:listitem text="Color" />
      <asp:listitem text="BackgroundColor" />
      <asp:listitem text="Border" />
   </asp:dropdownlist>

   <p><input type=submit value="Apply" runat="server"
         onServerClick="applyStyle" />
      <input type=submit value="Reset" runat="server"
         onServerClick="resetStyle" />
      
</form>
</div>

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

</body>
</html>