Ajax and append html: selector not work

Ajax and append html: selector not work

Hi at all.
I have a trouble.

I have this code:
<div class="calendar">
<table>
<tr>
  <th><a href="?nov">[<<]</a></th>
  <th >dicembre</th>
  <th><a href="?gen">[>>]</a></th>
</tr>
....
....
</table>
</div>

Is a Calendar.
When i click onto a link, the page was reloaded.
I need that the page was static.
So i use Ajax.
But when i append a new code, the selector change and not work more.
This is my JS code:
<script type="text/javascript">
//<![CDATA[
$(function() {
var navigation=$(".calendar tr:first a");
navigation.click(function(){
  var content_url=$(this).attr("href");
  $.ajax({
  method: "get",url: content_url+"&ajax=attivo",
  data:"form=ajax",
  //mostra il loading qundo clicco
  beforeSend: function(){},
  //nascondi il loading al caricamento
  complete: function(){},
  //visualizza l'html se esiste un valore di ritorno
  success: function(html){
   //inserisci l'html
   $(".calendar").html(html);
   ****
   }
  //chiudi ajax()
  });
//chiudi click()
return false;
});
});
//]]>
</script>

I have tried to intert a new declaration of variable navigation where i have inser 4 *. But not work yet.

Have you an idea to help me?

Thank.