我有一个登录脚本，并且当用户输入错误的登录详细信息时，如何在显示其设备信息后在用户屏幕上显示以下引导警报？在记录用户设备信息之后，我确实尝试添加了引导警报代码。但是，引导警报完全不显示。
<div class="alert alert-danger" role="alert">
Your device information has been logged due to wrong login details has been entered.
</div>
登录脚本代码
<?php
//PHP method to use cache memory to store details
session_start();
//Makes the "config.php" file available to be executed from this page
require_once('dbconfig/config.php');
require_once 'functions.php';
?>
<!DOCTYPE html>
<html>
<head>
<!-- Site title, CSS external file and font awesome -->
<title>Login Page - Created by Liam Docherty</title>
<link rel="stylesheet" href="https://use.fontawesome.com/releases/v5.6.3/css/all.css" integrity="sha384-UHRtZLI+pbxtHCWp1t77Bi1L4ZtiqrqD80Kn4Z8NTSRyMA2Fd33n5dQ8lWUE00s/" crossorigin="anonymous">
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.2.1/css/bootstrap.min.css" integrity="sha384-GJzZqFGwb1QTTN6wy59ffF1BuGJpLSa9DkKMp0DgiMDm4iYMj70gZWKYbI706tWS" crossorigin="anonymous">
<link rel="stylesheet" type="text/css" href="https://cdnjs.cloudflare.com/ajax/libs/animate.css/3.5.2/animate.css">
<link rel="stylesheet" type="text/css" href="design.css">
</head>
<body>
<!-- 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="https://www.linkedin.com/in/liam-docherty/">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>
</button>
<div class="collapse navbar-collapse" id="navbarResponsive">
<ul class="navbar-nav ml-auto">
<li class="nav-item active">
<a class="nav-link" href="http://webbrowserinfo.96.lt">Go back to Homepage <i class="fa fa-home"></i>
<span class="sr-only">(current)</span>
</a>
</li>
</ul>
</div>
</div>
</nav>
<!-- 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%">
</div>
</div>
<!-- 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 -->
<label><b>Username:</b></label>
<input type="text" placeholder="Enter Username:" name="username" required>
<!-- Password section -->
<label><b>Password:</b></label>
<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>
</a>
<hr>
<!-- Help -->
<a href="https://marketinginsidergroup.com/content-marketing/10-types-online-forms-use/">
<button type="button" class="register_btn">Help <i class="fas fa-question-circle"></i></button>
</a>
</div>
</form>
<?php
//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
saveLog(getBrowser(),'wrongLogin');
?>
<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.
</div>
<?php
}
}
}
?>
</body>
</html>
答案 0 :(得分：1)
Bootstrap警报不需要显示任何特殊内容，只需放置HTML元素，它们就会显示在您的页面上。
https://jsfiddle.net/anzre5v3/
<div class="alert alert-warning" role="alert">
This is a warning alert—check it out!
</div>
我认为您通过<script>window.location = "index.php?wrong_login"</script>进行的重定向存在问题，将其删除，您将看到警报。您的脚本再次将您重定向到同一页面，但没有发送表单，因此您的脚本无法处理