!php 连接到数据库$servername = localhost;$username = root;$password = 123;$dbname = myDB;$conn = new mysqli$servername $username $password $dbname;if $conn-connect_error die连接失败 $

修改以上代码，使登录失败时显示登录失败的提示，并提供重新输入的页面。

<?php
// 连接到数据库
$servername = "localhost";
$username = "root";
$password = "123";
$dbname = "myDB";

$conn = new mysqli($servername, $username, $password, $dbname);
if ($conn->connect_error) {
    die("连接失败: " . $conn->connect_error);
}

// 处理表单提交
if (isset($_SERVER["REQUEST_METHOD"]) && $_SERVER["REQUEST_METHOD"] == "POST") {
    $loginUsername = $_POST["loginUsername"];
    $loginPassword = $_POST["loginPassword"];

    // 检查用户名和密码是否匹配
    $sql = "SELECT * FROM users WHERE username='$loginUsername' AND password='$loginPassword'";
    $result = $conn->query($sql);

    if ($result->num_rows > 0) {
        echo "登录成功"; 
        header("Location: 1.html");
        exit;
    } else {
        echo "用户名或密码错误";
        echo "<br>";
        echo "<a href='login.html'>重新输入</a>";
    }
}

$conn->close();
?>

在登录失败的情况下，会显示"用户名或密码错误"的提示，并提供一个链接"重新输入"，点击该链接将跳转到名为"login.html"的页面，用户可以重新输入用户名和密码