How to change the login hyper link to logout when successfully logged in

[Adrock952]

I have a link on my site which obviously says "Login" where users log in.

I would like that link to be changed to "Logout" when the user has successfully logged in and the session has been created and when the user logs out, i would like the link changed back to "Login" without having to refresh the page.

here is my login page
[PHP]<?php

if (is_authed_user ())
{
print ('You are already logged in, <a href="index.php ">click here</a> to go back.');
}
else
{

if (!isset($_POST['submit']))
{
echo "<h2>Memebe r Login</h2><hr />";
// Show the form
include 'includes/login_form.inc. php';
}
else
{
$username = check_input($_P OST['username']);
$password = check_input($_P OST['password']);

// Try and login with the given username & pass
$result = user_login($use rname, $password);

if ($result != 'Correct')
{
echo "<h2>Memebe r Login</h2><hr />";
// Reshow the form with the error
$login_error = $result;
include 'includes/login_form.inc. php';
}
else
{
echo "<h2>Welcom e ".$_SESSION['username']."</h2><hr />";
echo 'Thank you for logging in, <a href="index.php ">click here</a> to go back.';
}
}
}
?>[/PHP] and the function to log the user in if you need it
[PHP]function user_login($use rname, $password)
{
// Try and get the salt from the database using the username
$query = "select salt from users where username='$user name' limit 1";
$result = mysql_query($qu ery);
$user = mysql_fetch_arr ay($result);

// Using the salt, encrypt the given password to see if it
// matches the one in the database
$encrypted_pass = md5(md5($passwo rd).$user['salt']);

// Try and get the user using the username & encrypted pass
$query = "select userid, username, user_level from users where username='$user name' and password='$encr ypted_pass'";
$result = mysql_query($qu ery);
$user = mysql_fetch_arr ay($result);
$numrows = mysql_num_rows( $result);

$userid = $user['userid'];
$user_level = $user['user_level'];

// Now encrypt the data to be stored in the session
$encrypted_id = md5($user['userid']);
$encrypted_name = md5($user['username']);
$encrypted_user = md5($user['user_level']);

// Store the data in the session
$_SESSION['userid'] = $userid;
$_SESSION['username'] = $username;
$_SESSION['user_level'] = $user_level;
$_SESSION['encrypted_id'] = $encrypted_id;
$_SESSION['encrypted_name '] = $encrypted_name ;
$_SESSION['encrypted_user '] = $encrypted_user ;


if ($numrows == 1)
{
return 'Correct';
}
else
{
return false;
}
}[/PHP]

all i have for the logout page is a simple session_unset() and session_destroy ()

This seems such a simple task but don't know where to start.

I presume the ajax would go after this in the login form to change the link from login to logout
[PHP]$result = user_login($use rname, $password);[/PHP]
If anyone has any ideas how i would do this i would be very grateful

[acoder]

Give the link an id. When the user has successfully logged in, i.e. readyState is 4 and you've validated that it's correct, change the link text: document.getEle mentById(linkID ).innerHTML="Lo gout".