【HTML】利用localstrange临时存储数据

前言

通过本地存储（Local Storage），web 应用程序能够在用户浏览器中对数据进行本地的存储。

在 HTML5 之前，应用程序数据只能存储在 cookie 中，包括每个服务器请求。本地存储则更安全，并且可在不影响网站性能的前提下将大量数据存储于本地。

与 cookie 不同，存储限制要大得多（至少5MB），并且信息不会被传输到服务器。

本地存储经由起源地（origin）（经由域和协议）。所有页面，从起源地，能够存储和访问相同的数据。

注意：localstrange里的数据不是永久保存的，它可能会在浏览器自动清理或手动删除后消失。

例子

Example：登录界面

项目说明

利用localstrange做一个登录、注册页面，可以立即注册和登录。

项目图片

如果你有服务器，将数据存储在服务器上是不二之选。但是没有服务器，我们也可以通过一下方法完成此操作。

思路

确定临时变量：登录、注册的账号密码，状态
明确如何调用。

由于存储变量的单一，重复注册会覆盖之前的数据。

过程

HTML样式

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Login</title>
<style>
  body {
    font-family: Arial, sans-serif;
    background-color: #f4f4f4;
  }
  .container {
    width: 300px;
    margin: 0 auto;
    background-color: #fff;
    padding: 20px;
    border-radius: 5px;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
  }
  h2 {
    text-align: center;
  }
  label {
    font-weight: bold;
  }
  input[type="text"],
  input[type="password"],
  button {
    width: 100%;
    margin-bottom: 10px;
    padding: 8px;
    box-sizing: border-box;
  }
  button {
    background-color: #4caf50;
    color: #fff;
    border: none;
    cursor: pointer;
  }
  button:hover {
    background-color: #45a049;
  }
</style>
</head>
<body>

<div class="container">
  <h2>Login</h2>
  <form id="loginForm">
    <label for="loginUsername">Username:</label>
    <input type="text" id="loginUsername" name="loginUsername" required><br>
    <label for="loginPassword">Password:</label>
    <input type="password" id="loginPassword" name="loginPassword" required><br><br>
    <button type="button" onclick="login()">Login</button>
    <button type="button" onclick="window.location.href = 'reg.html';">Register</button>
  </form>
</div>
</body>
</html>

定义

<script>
function login() {
  var username = document.getElementById("loginUsername").value;
  var password = document.getElementById("loginPassword").value;
  var storedUsername = localStorage.getItem("username");
  var storedPassword = localStorage.getItem("password");}
</script>

调用

<script>
function login() {
  var username = document.getElementById("loginUsername").value;
  var password = document.getElementById("loginPassword").value;
  var storedUsername = localStorage.getItem("username");
  var storedPassword = localStorage.getItem("password");
  if (username === storedUsername && password === storedPassword) {
    alert("Login successful!");
    window.location.href = 'https://minecraftsep.github.io/';
  } else {
    alert("Invalid username or password.");
  }
}
</script>

HTML样式：

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Register</title>
<style>
  body {
    font-family: Arial, sans-serif;
    background-color: #f4f4f4;
  }
  .container {
    width: 300px;
    margin: 0 auto;
    background-color: #fff;
    padding: 20px;
    border-radius: 5px;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
  }
  h2 {
    text-align: center;
  }
  label {
    font-weight: bold;
  }
  input[type="text"],
  input[type="password"],
  button {
    width: 100%;
    margin-bottom: 10px;
    padding: 8px;
    box-sizing: border-box;
  }
  button {
    background-color: #4caf50;
    color: #fff;
    border: none;
    cursor: pointer;
  }
  button:hover {
    background-color: #45a049;
  }
</style>
</head>
<body>

<div class="container">
  <h2>Register</h2>
  <form id="registerForm">
    <label for="regUsername">Username:</label>
    <input type="text" id="regUsername" name="regUsername" required><br>
    <label for="regPassword">Password:</label>
    <input type="password" id="regPassword" name="regPassword" required><br><br>
    <button type="button" onclick="register()">Register</button>
  </form>
</div>
</body>
</html>

2.定义+调用

<script>
function register() {
  var username = document.getElementById("regUsername").value;
  var password = document.getElementById("regPassword").value;
  if (username && password) {
    localStorage.setItem("username", username);
    localStorage.setItem("password", password);
    alert("Registration successful!");
    window.location.href = 'index.html';
  } else {
    alert("Please enter both username and password.");
  }
}
</script>

完整代码 –>

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Login</title>
<style>
  body {
    font-family: Arial, sans-serif;
    background-color: #f4f4f4;
  }
  .container {
    width: 300px;
    margin: 0 auto;
    background-color: #fff;
    padding: 20px;
    border-radius: 5px;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
  }
  h2 {
    text-align: center;
  }
  label {
    font-weight: bold;
  }
  input[type="text"],
  input[type="password"],
  button {
    width: 100%;
    margin-bottom: 10px;
    padding: 8px;
    box-sizing: border-box;
  }
  button {
    background-color: #4caf50;
    color: #fff;
    border: none;
    cursor: pointer;
  }
  button:hover {
    background-color: #45a049;
  }
</style>
</head>
<body>

<div class="container">
  <h2>Login</h2>
  <form id="loginForm">
    <label for="loginUsername">Username:</label>
    <input type="text" id="loginUsername" name="loginUsername" required><br>
    <label for="loginPassword">Password:</label>
    <input type="password" id="loginPassword" name="loginPassword" required><br><br>
    <button type="button" onclick="login()">Login</button>
    <button type="button" onclick="window.location.href = 'reg.html';">Register</button>
  </form>
</div>

<script>
function login() {
  var username = document.getElementById("loginUsername").value;
  var password = document.getElementById("loginPassword").value;
  var storedUsername = localStorage.getItem("username");
  var storedPassword = localStorage.getItem("password");
  if (username === storedUsername && password === storedPassword) {
    alert("Login successful!");
    window.location.href = 'https://minecraftsep.github.io/';
  } else {
    alert("Invalid username or password.");
  }
}
</script>

</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Register</title>
<style>
  body {
    font-family: Arial, sans-serif;
    background-color: #f4f4f4;
  }
  .container {
    width: 300px;
    margin: 0 auto;
    background-color: #fff;
    padding: 20px;
    border-radius: 5px;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
  }
  h2 {
    text-align: center;
  }
  label {
    font-weight: bold;
  }
  input[type="text"],
  input[type="password"],
  button {
    width: 100%;
    margin-bottom: 10px;
    padding: 8px;
    box-sizing: border-box;
  }
  button {
    background-color: #4caf50;
    color: #fff;
    border: none;
    cursor: pointer;
  }
  button:hover {
    background-color: #45a049;
  }
</style>
</head>
<body>

<div class="container">
  <h2>Register</h2>
  <form id="registerForm">
    <label for="regUsername">Username:</label>
    <input type="text" id="regUsername" name="regUsername" required><br>
    <label for="regPassword">Password:</label>
    <input type="password" id="regPassword" name="regPassword" required><br><br>
    <button type="button" onclick="register()">Register</button>
  </form>
</div>

<script>
function register() {
  var username = document.getElementById("regUsername").value;
  var password = document.getElementById("regPassword").value;
  if (username && password) {
    localStorage.setItem("username", username);
    localStorage.setItem("password", password);
    alert("Registration successful!");
    window.location.href = 'index.html';
  } else {
    alert("Please enter both username and password.");
  }
}
</script>

</body>
</html>

Exercise: 图片中转站

项目图片 –>

源代码请见评论区。

总结

localstrange可以临时存放数据，但不建议长久存放。

推荐订阅源

Minecraft-Sep

前言

例子