Code

<?php
session_start();
    if (isset($_POST['login'])){
        require 'connect.php';
        $username=$_POST['username'];
        $password=$_POST['password'];
        //$username=stripslashes($username);
        //$password=stripslashes($password);
        //$username=mysql_real_escape_string($username);
        //$password=mysql_real_escape_string($password);
        mysqli_query($con, "select * from customer_table where username = '$username' and password = '$password'");
        $numrows = mysqli_num_rows($result);
         if($numrows > 0)
{
echo $numrows;
}
        if(mysqli_num_rows($result)==1){
            $_SESSION['username'] = $username;
            header('location: cluserhome.php');
    }
            else
                echo "Username or password is invalid.";
}
    ?>
<html>
<head>
    <title> Capslove/Login</title>
    <link rel = "stylesheet" type = "text/css" href = "clh.css">
</head>
<body>
    <?php
        include '@logo.php';
    ?>
    <div class="board">
    <form name="login" method="post" action="cllogin.php?action=login">
        <table align="center">
            <tr>
            <th colspan="2">Login</th>
            </tr>

            <tr>
                <td colspan="2"><input type="text" placeholder="Username" name="username" required="required">
                </td>
            </tr>
            <tr>
                <td colspan="2"><input type="password" placeholder="Password" name="password" required="required">
                </td>
            </tr>
            <tr>
                <td><input type="submit" value="Log in" name = "login"></td>
                <td><a href="clforgot.php">Forgot password?</a></td>
                </tr>
        </table>
        </form>
    </div>

    <?php

        include '@footer.php';
    ?>

</body>

</html>