在PHP中實作登入跳到HTML頁面需要使用一些基本的程式設計技巧。以下是實作過程的具體步驟：
首先，需要建立一個登入頁面，以收集使用者的登入憑證。此頁面將用於驗證使用者憑證和介紹登入使用者到其他受保護的頁面。
在PHP中，可以建立驗證邏輯，以驗證使用者輸入的憑證是否有效。可以使用MySQL資料庫和PHP會話來實作這個功能。具體步驟如下：
下面是一個驗證邏輯的程式碼範例：
<?php
// Start the session
session_start();
// Check if the user is already logged in
if(isset($_SESSION["loggedin"]) && $_SESSION["loggedin"] === true){
header("location: welcome.php");
exit;
}
// Include config file
require_once "config.php";
// Define variables and initialize with empty values
$username = $password = "";
$username_err = $password_err = "";
// Processing form data when form is submitted
if($_SERVER["REQUEST_METHOD"] == "POST"){
// Check if username is empty
if(empty(trim($_POST["username"]))){
$username_err = "Please enter username.";
} else{
$username = trim($_POST["username"]);
}
// Check if password is empty
if(empty(trim($_POST["password"]))){
$password_err = "Please enter your password.";
} else{
$password = trim($_POST["password"]);
}
// Validate credentials
if(empty($username_err) && empty($password_err)){
// Prepare a select statement
$sql = "SELECT id, username, password FROM users WHERE username = ?";
if($stmt = $mysqli->prepare($sql)){
// Bind variables to the prepared statement as parameters
$stmt->bind_param("s", $param_username);
// Set parameters
$param_username = $username;
// Attempt to execute the prepared statement
if($stmt->execute()){
// Store result
$stmt->store_result();
// Check if username exists, if yes then verify password
if($stmt->num_rows == 1){
// Bind result variables
$stmt->bind_result($id, $username, $hashed_password);
if($stmt->fetch()){
if(password_verify($password, $hashed_password)){
// Password is correct, so start a new session
session_start();
// Store data in session variables
$_SESSION["loggedin"] = true;
$_SESSION["id"] = $id;
$_SESSION["username"] = $username;
// Redirect user to welcome page
header("location: welcome.php");
} else{
// Display an error message if password is not valid
$password_err = "The password you entered was not valid.";
}
}
} else{
// Display an error message if username doesn't exist
$username_err = "No account found with that username.";
}
} else{
echo "Oops! Something went wrong. Please try again later.";
}
}
// Close statement
$stmt->close();
}
// Close connection
$mysqli->close();
}
?>在PHP中，可以使用會話變數來驗證使用者是否已登入。如果使用者已經登入，可以顯示受保護的HTML頁面。否則，需要重定向到登入頁面。
在登入頁面中，可以使用PHP程式碼來處理表單提交和驗證。具體步驟如下：
以下是一個有登入表單和PHP程式碼的範例程式碼：
<?php
// Initialize the session
session_start();
// Check if the user is already logged in, if yes then redirect him to welcome page
if(isset($_SESSION["loggedin"]) && $_SESSION["loggedin"] === true){
header("location: welcome.html");
exit;
}
// Include config file
require_once "config.php";
// Define variables and initialize with empty values
$username = $password = "";
$username_err = $password_err = "";
// Processing form data when form is submitted
if($_SERVER["REQUEST_METHOD"] == "POST"){
// Check if username is empty
if(empty(trim($_POST["username"]))){
$username_err = "Please enter username.";
} else{
$username = trim($_POST["username"]);
}
// Check if password is empty
if(empty(trim($_POST["password"]))){
$password_err = "Please enter your password.";
} else{
$password = trim($_POST["password"]);
}
// Validate credentials
if(empty($username_err) && empty($password_err)){
// Prepare a select statement
$sql = "SELECT id, username, password FROM users WHERE username = ?";
if($stmt = $mysqli->prepare($sql)){
// Bind variables to the prepared statement as parameters
$stmt->bind_param("s", $param_username);
// Set parameters
$param_username = $username;
// Attempt to execute the prepared statement
if($stmt->execute()){
// Store result
$stmt->store_result();
// Check if username exists, if yes then verify password
if($stmt->num_rows == 1){
// Bind result variables
$stmt->bind_result($id, $username, $hashed_password);
if($stmt->fetch()){
if(password_verify($password, $hashed_password)){
// Password is correct, so start a new session
session_start();
// Store data in session variables
$_SESSION["loggedin"] = true;
$_SESSION["id"] = $id;
$_SESSION["username"] = $username;
// Redirect user to welcome page
header("location: welcome.html");
} else{
// Display an error message if password is not valid
$password_err = "The password you entered was not valid.";
}
}
} else{
// Display an error message if username doesn't exist
$username_err = "No account found with that username.";
}
} else{
echo "Oops! Something went wrong. Please try again later.";
}
}
// Close statement
$stmt->close();
}
// Close connection
$mysqli->close();
}
?>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Login</title>
<style>
body{ font: 14px sans-serif; }
.wrapper{ width: 350px; padding: 20px; }
</style>
</head>
<body>
<div class="wrapper">
<h2>Login</h2>
<p>Please fill in your credentials to login.</p>
<form action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]); ?>" method="post">
<div <?php echo (!empty($username_err)) ? 'has-error' : ''; ?>">
<label>Username</label>
<input type="text" name="username" class="form-control" value="<?php echo $username; ?>">
<span <?php echo (!empty($username_err)) ? 'help-block' : ''; ?>"><?php echo $username_err; ?></span>
</div>
<div <?php echo (!empty($password_err)) ? 'has-error' : ''; ?>">
<label>Password</label>
<input type="password" name="password" class="form-control">
<span <?php echo (!empty($password_err)) ? 'help-block' : ''; ?>"><?php echo $password_err; ?></span>
</div>
<div class="form-group">
<input type="submit" class="btn btn-primary" value="Login">
</div>
<p>Don't have an account? <a href="register.html">Sign up now</a>.</p>
</form>
</div>
</body>
</html>以上就是透過PHP實作使用者登入跳到HTML頁面的基本步驟和程式碼範例。
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