How can I make my bootstrap alert display at a specific time?

I have a login script and when the user inputs the wrong login details, how can I display the bootstrap alert below to display on the users screen after their device information is display? I did try add the bootstrap alert code after the users device information is logged. However, the bootstrap alert doesn’t display at all.

<div class="alert alert-danger" role="alert">
      Your device information has been logged due to wrong login details has been entered.

Login script code

//PHP method to use cache memory to store details
//Makes the "config.php" file available to be executed from this page
require_once 'functions.php';

    <!DOCTYPE html>

        <!-- Site title, CSS external file and font awesome -->
        <title>Login Page - Created by Liam Docherty</title>
        <link rel="stylesheet" href="" integrity="sha384-UHRtZLI+pbxtHCWp1t77Bi1L4ZtiqrqD80Kn4Z8NTSRyMA2Fd33n5dQ8lWUE00s/" crossorigin="anonymous">
        <link rel="stylesheet" href="" integrity="sha384-GJzZqFGwb1QTTN6wy59ffF1BuGJpLSa9DkKMp0DgiMDm4iYMj70gZWKYbI706tWS" crossorigin="anonymous">
        <link rel="stylesheet" type="text/css" href="">
        <link rel="stylesheet" type="text/css" href="design.css">

        <!-- Nav Bar-->
        <nav class="navbar navbar-expand-lg navbar-dark bg-dark fixed-bottom animated bounceInDown">
            <div class="container">
                <a class="navbar-brand text-uppercase" href="">handcrafted BY Liam Docherty <i class="far fa-copyright"></i></a>
                <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarResponsive" aria-controls="navbarResponsive" aria-expanded="false" aria-label="Toggle navigation">
                    <span class="navbar-toggler-icon"></span>
                <div class="collapse navbar-collapse" id="navbarResponsive">
                    <ul class="navbar-nav ml-auto">
                        <li class="nav-item active">
                            <a class="nav-link" href="">Go back to Homepage <i class="fa fa-home"></i>
                <span class="sr-only">(current)</span>

        <!-- Structure / Titles -->
        <div class="container">
            <div class="row animated bounceInDown">
                <div class="col text-center">
                    <h2>Login Form - Created by Liam Docherty</h2>
                    <img src="imgs/icon-person-512.png" class="mx-auto d-block" style="width:15%">

            <!-- THE FORM -->
            <!-- action="index.php" -- This shows where the PHP script that does the processing is located -->
            <!-- method="post" -- This aspect  identifies the action that will be performed with the data of the form. For example POST data to the "users" database -->
            <form action="index.php" method="post">
                <!-- Form/animation -->
                <div class="inner_container text-center animated bounceInDown">
                    <!-- Username section -->
                    <input type="text" placeholder="Enter Username:" name="username" required>
                    <!-- Password section -->
                    <input type="password" placeholder="Enter Password:" name="password" required>
                    <input type="hidden" name="login" value="true">
                    <!-- The Login button -->
                    <button class="login_button" type="submit">Login <i class="fas fa-sign-in-alt"></i></button>
                    <!-- The button that is linked to the "register.php" page -->
                    <a href="register.php">
                        <button type="button" class="register_btn">Register <i class="fas fa-user-plus"></i></button>
                    <!-- Help -->
                    <a href="">
                        <button type="button" class="register_btn">Help <i class="fas fa-question-circle"></i></button>
    //Condition, checking the Login button is pressed
    if (isset($_POST['login'])) {
        //The data from the Form (username & password) is stored into the @$username & @$passwordVariables
        //You use @ before a VARIABLE in PHP when you do not want to initialise the VARIABLE before using it
        @$username = $_POST['username'];
        @$password = $_POST['password'];

        //Statement that will SELECT the data from the "login" table, WHERE the Usename and Password typed match the typed ones
        //Once the database is checked, if login details match than it stores the data in the "$query" VARIABLE
        $query = "SELECT * FROM login WHERE username='$username' and password='$password' ";
        //echo $query;

        //This statement performs both the connection to the database using the values in the "$con" VARIABLE and
        //The SELECT statement stored in the "$query" VARIABLE
        $query_run = mysqli_query($con, $query);
        //echo mysql_num_rows($query_run);

        //IF the "$query_run" is run successfully, then
        if ($query_run) {
            //Check if the Username and Password exist in the database, if they exist
            if (mysqli_num_rows($query_run) > 0) {
                $row = mysqli_fetch_array($query_run, MYSQLI_ASSOC);

                $_SESSION['username'] = $username; //Username handle aspect
                $_SESSION['password'] = $password; //Password handle aspect

                //Sent the user to the "homepage.php" page
                header("Location: homepage.php");
            } else { //here the login failed
                <script>window.location = "index.php?wrong_login"</script>
                <div class="alert alert-danger" role="alert">
                    Your device information has been logged due to wrong login details has been entered.


hope this helps.

  var d = new Date();
  var h = d.getUTCHours();
  if (h >= 12) {
      '<div class="alert alert-warning alert-dismissible fade show" role="alert">' +
        'It is now 12pm! Time to take a break and recharge!' +
        '<button type="button" class="close" data-dismiss="alert" aria-label="Close">' +
        '<span aria-hidden="true">&times;</span>' +
        '</button>' +
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