Ajax -- use timer to control the content background

{This content is from Microsoft}

Source viewCode:

 1   <%  @ Page Language  =  "  C #  "  Autoeventwireup  =  "  True "  Codefile  =  "  Default. aspx. CS  "  Inherits  =  "  _ Default  "    %>  
  2   
  3     <!  Doctype HTML public "-// W3C // dtd xhtml 1.1 // en" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd"  >  
  4     <  Html  Xmlns = "Http://www.w3.org/1999/xhtml"  >  
  5     <  Head  ID  = "Head1"  Runat  = "Server"  >  
  6     <  Title >  Timer example Page  </  Title  >  
  7     <  Link  Href  = "Divstyles.css"  REL  = "Stylesheet"  Type  = "Text/CSS"    />  
  8     </  Head  >  
  9     <  Body  >  
  10     <  Form ID  = "Form1"  Runat  = "Server"  >  
  11     <  ASP: scriptmanager  ID  = "Scriptmanager1"  Runat  = "Server"     />  
 12     <  ASP: Timer  ID  = "Timer1"  Ontick  = "Timereffectick"  Runat  = "Server"  Interval  = "1000"     />  
  13    <  BR  />  
  14     <  HR  />  
  15     <  BR  />  
  16  Some content ..............  <  BR  />  
  17     <  BR  />  
  18     <  ASP: updatepanel  ID  = "Bannerpanel" Runat  = "Server"  Updatemode  = "Conditional"  >  
  19     <  Triggers  >  
  20     <  ASP: asyncpostbacktrigger  Controlid = "Timer1"     />  
  21     </  Triggers  >  
  22     <  Contenttemplate  >  
  23    <  ASP: Image  ID  = "Bannerimage"  Runat  = "Server"  Imageurl  = "~ /Banners/banner_1.gif"     />  & Nbsp;  
  24     </ Contenttemplate  >  
  25     </  ASP: updatepanel  >  
  26     <  BR  />  
  27    <  Div  >  
  28     & Nbsp;  Some more content ..........  <  BR  />  
  29     <  BR  /> 
  30     </  Div  >  
  31     </  Form  >  
  32     </  Body  > 
  33     </  Html  > 

 1     Protected     Void  Timereffectick (  Object  Sender, eventargs E)
  2   {
  3  Random randomclass  =     New  Random ();
  4     Int  N  =  Randomclass. Next (  1  ,  9  );
  5   Bannerimage. imageurl =  System. String. Concat (  "  Banners/banner _  "  , N. tostring (),  "  . Gif  "  );
  6   } 

The function of the code is to generate an arbitrary random number from 1 to 9 to select the rendering of different images.