Prevent Back Button after Logout in ASP.Net

Prevent the Back option after Log Out:

To prevent the user to go back on your web page once the user has logged out , follow the procedure as:

Step 1 Set a Session in the Login Page after proper validation of User Id and Password. For e.g.

Session["LoginId"]=txtLoginId.Text;

Step 2 In the Page_Load event of your master page include the following code:

protected void Page_Load(object sender, EventArgs e)
    {
        if(!IsPostBack)
        {
            if (Session["LoginId"] == null)
                Response.Redirect("frmLogin.aspx");
            else
            {
                Response.ClearHeaders();
                Response.AddHeader("Cache-Control", "no-cache, no-store, max-age=0, must-revalidate");
                Response.AddHeader("Pragma", "no-cache");
                            }
        }
    }

Step 3 Do clear the session on the Logout button as:

 Session.Abandon();
            Session.Clear();

By default when you press the browser's back button , it loads the page directly from the browser's cache but by implementing the code given in the step 2 , the page will be loaded and the page load event will fire.