Page is accessible even after user has logged out

After logout the user is redirected to home.aspx.. home.aspx uses master page.

In the home.aspx i have written the javascript to disable back button but it is not working

You need to place the script in content place holder of home.aspx within script tags

Yes sir,

I have done the same but still does not work.

<%@ Page Language="C#" MasterPageFile="~/Home.master" AutoEventWireup="true" CodeFile="home.aspx.cs" Inherits="home" %>

<asp:Content ID="Content1" ContentPlaceHolderID="head" runat="server">
<script type="text/javascript">
    function preventBack(){window.history.forward();}

    setTimeout("preventBack()", 0);

    window.onunload=function(){null};
</script>
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" runat="server">
<table width="800px" border="0" cellspacing="1" cellpadding="1">
  <tr>
    <td>
        <asp:Label ID="lblmessage" runat="server" Font-Bold="True" ForeColor="#FF3300"></asp:Label>
      </td>
    <td>&nbsp;</td>
  </tr>
  <tr>
    <td>&nbsp;</td>
    <td>&nbsp;</td>
  </tr>
</table>
</asp:Content>

You will need to place it on the page where you want to prevent user from going back.

In your case it is logout page, hence place the script there

At logout page load i have these methods:

When user is redirected to home.aspx after logout from home.aspx he must not move back

protected void Page_Load(object sender, EventArgs e)
    {
        Session.Abandon();
        Session.Clear();
        Session.RemoveAll();
        Response.Redirect("home.aspx");
    }