今天在練習寫網頁時，剛好要來有做到Dark Mode 的功能，那順便來記錄一下做法～
首先要先知道Dark Mode的運作原理。是如何知道你現在是Light Mode還是Dark Mode呢？
在知道原理後，我們要如何去實作“在一個標籤中同時有兩個模式的CSS”，這邊以Tailwind.css做示範
<body class="bg-white text-black dark:bg-darkBlue dark:text-white"
>123</html>
先設定好原本的CSS，在額外設定dark: Dark Mode 的樣式就好拉～
那其實這也沒什麼，但有一個問題就是，怎麼製作觸發的按鈕。我一開始還以為要全部手尻(汗)，但後來才發現其實Tailwind有幫我們做好了(佛心公司～佛心公司～🥰)
那這邊就有明明白白地跟你說拉～
- Toggle dark mode by checking user preference in the
<head>tag of your HTML (將下面這段代碼放在head標籤)
<script>
// On page load or when changing themes, best to add inline in `head` to avoid FOUC
if (localStorage.getItem('color-theme') === 'dark' || (!('color-theme' in localStorage) && window.matchMedia('(prefers-color-scheme: dark)').matches)) {
document.documentElement.classList.add('dark');
} else {
document.documentElement.classList.remove('dark')
}
</script>
- 最棒的地方來了，他直接提供現成的button SVG，直接複製貼上就行拉～
Create a <button> element that can be interacted with to manually change the theme color:<button id="theme-toggle" type="button" class="text-gray-500 dark:text-gray-400 hover:bg-gray-100 dark:hover:bg-gray-700 focus:outline-none focus:ring-4 focus:ring-gray-200 dark:focus:ring-gray-700 rounded-lg text-sm p-2.5">
<svg id="theme-toggle-dark-icon" class="hidden w-5 h-5" fill="currentColor" viewBox="0 0 20 20" xmlns="http://www.w3.org/2000/svg"><path d="M17.293 13.293A8 8 0 016.707 2.707a8.001 8.001 0 1010.586 10.586z"></path></svg>
<svg id="theme-toggle-light-icon" class="hidden w-5 h-5" fill="currentColor" viewBox="0 0 20 20" xmlns="http://www.w3.org/2000/svg"><path d="M10 2a1 1 0 011 1v1a1 1 0 11-2 0V3a1 1 0 011-1zm4 8a4 4 0 11-8 0 4 4 0 018 0zm-.464 4.95l.707.707a1 1 0 001.414-1.414l-.707-.707a1 1 0 00-1.414 1.414zm2.12-10.607a1 1 0 010 1.414l-.706.707a1 1 0 11-1.414-1.414l.707-.707a1 1 0 011.414 0zM17 11a1 1 0 100-2h-1a1 1 0 100 2h1zm-7 4a1 1 0 011 1v1a1 1 0 11-2 0v-1a1 1 0 011-1zM5.05 6.464A1 1 0 106.465 5.05l-.708-.707a1 1 0 00-1.414 1.414l.707.707zm1.414 8.486l-.707.707a1 1 0 01-1.414-1.414l.707-.707a1 1 0 011.414 1.414zM4 11a1 1 0 100-2H3a1 1 0 000 2h1z" fill-rule="evenodd" clip-rule="evenodd"></path></svg>
</button>
啊就給他複製到你的網頁，他會長這樣：
- Add the following JavaScript inside your main file to handle the click events on the
<button>element 再新增一個JavaScript檔，將下列內容貼近去，並將其JavaScript檔引入html
var themeToggleDarkIcon = document.getElementById('theme-toggle-dark-icon');
var themeToggleLightIcon = document.getElementById('theme-toggle-light-icon');
// Change the icons inside the button based on previous settings
if (localStorage.getItem('color-theme') === 'dark' || (!('color-theme' in localStorage) && window.matchMedia('(prefers-color-scheme: dark)').matches)) {
themeToggleLightIcon.classList.remove('hidden');
} else {
themeToggleDarkIcon.classList.remove('hidden');
}
var themeToggleBtn = document.getElementById('theme-toggle');
themeToggleBtn.addEventListener('click', function() {
// toggle icons inside button
themeToggleDarkIcon.classList.toggle('hidden');
themeToggleLightIcon.classList.toggle('hidden');
// if set via local storage previously
if (localStorage.getItem('color-theme')) {
if (localStorage.getItem('color-theme') === 'light') {
document.documentElement.classList.add('dark');
localStorage.setItem('color-theme', 'dark');
} else {
document.documentElement.classList.remove('dark');
localStorage.setItem('color-theme', 'light');
}
// if NOT set via local storage previously
} else {
if (document.documentElement.classList.contains('dark')) {
document.documentElement.classList.remove('dark');
localStorage.setItem('color-theme', 'light');
} else {
document.documentElement.classList.add('dark');
localStorage.setItem('color-theme', 'dark');
}
}
});
這邊可以稍微留意一下，步驟一根步驟三的內容其實大同相似，差別是在於：
第一步是提供給一開始渲染網站時，是否要轉成Dark Mode 的依據，那這個依據會取決於localStorage是否有Dark Mode 的紀錄。
第三步的代碼，在更改Dark Mode的同時，也會更新localStorage，那假入筆者手殘「啪」一聲，關掉原本的網頁，再重新開啟時，就會保留原本Dark Mode的依據。
