php change sign in to sign out after user signs in

Question

signin.php:

<?php
include("config.php");

if (mysqli_connect_errno())
{
   echo "MySQLi Connection was not established: " . mysqli_connect_error();
}

if(isset($_POST['login']))
{
   $username = mysqli_real_escape_string($con,$_POST['username']);
   $password = mysqli_real_escape_string($con,$_POST['password']);

   $sel_user = "SELECT * FROM user WHERE username='$username' AND password='$password'";
   $run_user = mysqli_query($con, $sel_user);

   $check_user = mysqli_num_rows($run_user);

   if($check_user = 2)
   {
      $_SESSION['username']=$username;
      echo "<script>window.open('index.php','_self')</script>";
   }
   else 
   {
      echo "<script>alert('Email or password is not correct, try again')</script>";
   }
}

?>

index.php:

<ul class="nav navbar-nav navbar-right">
     <li><a href="mypage.html">My Page</a></li>
     <li><a href="signup.php">Sign up</a></li>
     <li><a href="signin.php">Sign in</a></li>
</ul>

So, there are three options in my index.php, My Page, Sign up, and Sign in. I want to change Sign in to Sign out when user logs in and display my name on the left side of My Page option. How can I modify my codes? please don't just say "You need ~~~". please indicate where exactly add it as well. Thank you

`if($check_user = 2)` guess what that does. Edit: It "assigns", so it will always be true and equaling two. — Funk Forty Niner, Apr 29 '16 at 16:16
You shouldnt expext people to actually fix your code. People will only tell you what you should try to get closer to your goal. — Celoain, Apr 29 '16 at 16:20
possible duplicate of [The 3 different equals](http://stackoverflow.com/questions/2063480/the-3-different-equals) — Funk Forty Niner, Apr 29 '16 at 16:21
@Fred-ii- Hardly. It's not a good question, but the point of this question is dynamic HTML rather than a bug in the sign in script. — ArtOfCode, Apr 29 '16 at 16:23
[Little Bobby](http://bobby-tables.com/) says [your script is at risk for SQL Injection Attacks.](http://stackoverflow.com/questions/60174/how-can-i-prevent-sql-injection-in-php) Learn about [prepared](http://en.wikipedia.org/wiki/Prepared_statement) statements for [MySQLi](http://php.net/manual/en/mysqli.quickstart.prepared-statements.php). Even [escaping the string](http://stackoverflow.com/questions/5741187/sql-injection-that-gets-around-mysql-real-escape-string) is not safe! — Jay Blanchard, Apr 29 '16 at 16:42
**Never store plain text passwords!** Please use PHP's [built-in functions](http://jayblanchard.net/proper_password_hashing_with_PHP.html) to handle password security. If you're using a PHP version less than 5.5 you can use the `password_hash()` [compatibility pack](https://github.com/ircmaxell/password_compat). Make sure that you [don't escape passwords](http://stackoverflow.com/q/36628418/1011527) or use any other cleansing mechanism on them before hashing. Doing so *changes* the password and causes unnecessary additional coding. — Jay Blanchard, Apr 29 '16 at 16:43
No - you should use PHP's built-in password hashing functions. BCRYPT is the current default. — Jay Blanchard, Apr 29 '16 at 17:06

score 1 · Answer 1 · answered Apr 29 '16 at 16:22

In place of

<li><a href="signin.php">Sign in</a></li>

you need

<li>
    <?php
        if(isset($_SESSION['username'])) { ?>
            <a href="signout.php">Sign out</a>
    <?php 
        } else { ?>
            <a href="signin.php">Sign in</a>
    <?php
        } ?>
</li>

BUT

You have massive security issues there. You're storing passwords in plain text in your database, by the looks of it. You need to fix this. Now.

php change sign in to sign out after user signs in

1 Answers1

BUT

Linked