更新会话变量而不刷新页面[关闭]

I need to update the session variable on page 1, when click on a link in iframe (external page). session variable is successfully set when i click on iframe's link. the problem is i need to refresh the page 1 to update that session variable on page1.

how to resolve this.any ajax , jquery help. THanks

HTML a href link:

<a href="#" id="clickme">Update Session</a>

jQuery codes:

You can send data with line of data: { varname: 'here we go'}

<script src="http://code.jquery.com/jquery-1.10.1.min.js"></script>
<script>
$("#clickme").click(function(e) {
    e.preventDefault();
    $.ajax({
        type:'POST',
        url:'update.php',
        data: { varname: 'here we go'},
        success:function(response){
           alert(response);
        }
    });
});
</script>

update.php file:

You can get sent var with $_POST["varname"]

<?php
   $_SESSION["varname"] = $_POST["varname"];
   echo $_SESSION["varname"];
?>