回到陆地上。让你的博客从白天到晚上，无需群岛！

既然你可以为交互式元素构建 Astro 岛，请不要忘记仅使用普通 JavaScript 和 CSS 就可以走得很远！

¥Now that you can build Astro islands for interactive elements, don’t forget that you can go pretty far with just vanilla JavaScript and CSS!

让我们构建一个可点击的图标，让你的用户使用另一个 <script> 标签在浅色或夜间模式之间切换以实现交互…没有框架 JavaScript 发送到浏览器。

¥Let’s build a clickable icon to let your users toggle between light or dark mode using another <script> tag for interactivity… with no framework JavaScript sent to the browser.

准备好……

仅使用 JavaScript 和 CSS 构建交互式主题切换
向浏览器发送尽可能少的 JavaScript！

添加主题切换图标并设置其样式

¥Add and style a theme toggle icon

Create a new file at src/components/ThemeIcon.astro and paste the following code into it:

---
---
<button id="themeToggle">
  <svg width="30px" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24">
    <path class="sun" fill-rule="evenodd" d="M12 17.5a5.5 5.5 0 1 0 0-11 5.5 5.5 0 0 0 0 11zm0 1.5a7 7 0 1 0 0-14 7 7 0 0 0 0 14zm12-7a.8.8 0 0 1-.8.8h-2.4a.8.8 0 0 1 0-1.6h2.4a.8.8 0 0 1 .8.8zM4 12a.8.8 0 0 1-.8.8H.8a.8.8 0 0 1 0-1.6h2.5a.8.8 0 0 1 .8.8zm16.5-8.5a.8.8 0 0 1 0 1l-1.8 1.8a.8.8 0 0 1-1-1l1.7-1.8a.8.8 0 0 1 1 0zM6.3 17.7a.8.8 0 0 1 0 1l-1.7 1.8a.8.8 0 1 1-1-1l1.7-1.8a.8.8 0 0 1 1 0zM12 0a.8.8 0 0 1 .8.8v2.5a.8.8 0 0 1-1.6 0V.8A.8.8 0 0 1 12 0zm0 20a.8.8 0 0 1 .8.8v2.4a.8.8 0 0 1-1.6 0v-2.4a.8.8 0 0 1 .8-.8zM3.5 3.5a.8.8 0 0 1 1 0l1.8 1.8a.8.8 0 1 1-1 1L3.5 4.6a.8.8 0 0 1 0-1zm14.2 14.2a.8.8 0 0 1 1 0l1.8 1.7a.8.8 0 0 1-1 1l-1.8-1.7a.8.8 0 0 1 0-1z"/>
    <path class="moon" fill-rule="evenodd" d="M16.5 6A10.5 10.5 0 0 1 4.7 16.4 8.5 8.5 0 1 0 16.4 4.7l.1 1.3zm-1.7-2a9 9 0 0 1 .2 2 9 9 0 0 1-11 8.8 9.4 9.4 0 0 1-.8-.3c-.4 0-.8.3-.7.7a10 10 0 0 0 .3.8 10 10 0 0 0 9.2 6 10 10 0 0 0 4-19.2 9.7 9.7 0 0 0-.9-.3c-.3-.1-.7.3-.6.7a9 9 0 0 1 .3.8z"/>
  </svg>
</button>

<style>
  #themeToggle {
    border: 0;
    background: none;
  }
  .sun { fill: black; }
  .moon { fill: transparent; }

  :global(.dark) .sun { fill: transparent; }
  :global(.dark) .moon { fill: white; }
</style>

Add the icon to Header.astro so that it will be displayed on all pages. Don’t forget to import the component.

---
import Hamburger from './Hamburger.astro';
import Navigation from './Navigation.astro';
import ThemeIcon from './ThemeIcon.astro';
---
<header>
  <nav>
    <Hamburger />
    <ThemeIcon />
    <Navigation />
  </nav>
</header>

Visit your browser preview at http://localhost:4321 to see the icon now on all your pages. You can try clicking it, but you have not written a script to make it interactive yet.

为深色主题添加 CSS 样式

¥Add CSS styling for a dark theme

选择一些在夜间模式下使用的替代颜色。

¥Choose some alternate colors to use in dark mode.

In global.css, define some dark styles. You can choose your own, or copy and paste:

html.dark {
  background-color: #0d0950;
  color: #fff;
}

.dark .nav-links a {
  color: #fff;
}

添加客户端交互

¥Add client-side interactivity

要向 Astro 组件添加交互性，你可以使用 <script> 标签。该脚本可以检查并设置 localStorage 中的当前主题，并在单击图标时切换主题。

¥To add interactivity to an Astro component, you can use a <script> tag. This script can check and set the current theme from localStorage and toggle the theme when the icon is clicked.

Add the following <script> tag in src/components/ThemeIcon.astro after your <style> tag:

<style>
  .sun { fill: black; }
  .moon { fill: transparent; }

  :global(.dark) .sun { fill: transparent; }
  :global(.dark) .moon { fill: white; }
</style>

<script is:inline>
  const theme = (() => {
    if (typeof localStorage !== 'undefined' && localStorage.getItem('theme')) {
      return localStorage.getItem('theme') ?? "light";
    }
    if (window.matchMedia('(prefers-color-scheme: dark)').matches) {
      return 'dark';
    }
      return 'light';
  })();

  if (theme === 'light') {
    document.documentElement.classList.remove('dark');
  } else {
    document.documentElement.classList.add('dark');
  }

  window.localStorage.setItem('theme', theme);

  const handleToggleClick = () => {
    const element = document.documentElement;
    element.classList.toggle("dark");

    const isDark = element.classList.contains("dark");
    localStorage.setItem("theme", isDark ? "dark" : "light");
  }

  document.getElementById("themeToggle")?.addEventListener("click", handleToggleClick);
</script>

Check your browser preview at http://localhost:4321 and click the theme icon. Verify that you can change between light and dark modes.

清单

¥Checklist

当我不想添加框架时，我可以使用 JavaScript 进行交互。

资源

¥Resources

Astro 中的客户端 <script>

回到陆地上。让你的博客从白天到晚上，无需群岛！

添加主题切换图标并设置其样式

为深色主题添加 CSS 样式

添加客户端交互

测试你的知识

清单

资源