用ajax实现Session永不过期

<title></title>
    <script src="js/Jquery1.7.js" type="text/javascript"></script>
    <script type="text/javascript">
        $(function () {
            function post() {
                $.ajax({
                    type: "post",
                    contentType: "application/json",
                    url: "WebBlock.aspx"
                })
            }

        })
    </script>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <asp:TextBox ID="TextBox1" runat="server" Height="409px" TextMode="MultiLine"
            Width="449px"></asp:TextBox>
        <asp:Button ID="Button1"
            runat="server" Text="保存" OnClientClick="" onclick="Button1_Click" />
    </div>
    </form>