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Dark Mode in 3 Lines of CSS and Other Adventures

Mads Stoumann on April 29, 2023

Dark Mode is a design trend where the color scheme of a website is changed to a dark background with light-colored text and elements. It's also ref...
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Lionel Wong • • Edited 
<fieldset id="colorScheme">
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colorScheme.addEventListener(...)
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What is the general consensus in the community about referencing elements like this? As opposed to:

document.getElementById('colorScheme').addEventListener(...)
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Isn't it considered unsafe and error-prone? I don't really remember, it's rarely seen in the wild, perhaps for a reason.

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Mads Stoumann •

When I write example-code for articles, I tend to omit selectors, because I want to focus on what the code does, rather than how to select a Node in the DOM.
I assume most of Dev.to's readers knows how to do that anyway, and might want to use their own selectors (class-based, attribute-based, something else?) instead of just copy/pasting the code.

But I could be wrong! So thank you for your feedback — I've added this to the article:

const colorScheme = document.getElementById('colorScheme');
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Wade Zimmerman •

It's best practice to use document.getElementById over the global variable because defining a local variable colorScheme would take precedence. It's also annoying to debug these global variables because they are not explicitly defined. When searching for something like colorScheme = you won't find anything, and finding something like colorScheme.addEventListener tells you nothing about the type of variable. However, finding document.getElementById tells you it's a DOM element.

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Adam Crockett 🌀 •

I vote that implicit code is dangerous code and explicit code is safe code and there is no grey area 🫣

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Mads Stoumann •

(see updated feedback above)

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Anthony Fung •

Very cool.

I've used this scheme of system themed colours when programming Windows desktop apps.

I didn't know it existed in CSS though - thanks!

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Mads Stoumann •

👍🏻

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Hector Sosa •

Very detailed post! Great share! @madsstoumann Framing these screenshots would've been chef's kiss. I've built a simple OSS tool to help with screenshots with ease. Give it a shot and let me know what you think.

github.com/ekqt/screenshot

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Mads Stoumann •

Cool!

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Obaseki Noruwa •

Love this ❤️, Thanks for sharing.

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Mads Stoumann •

👍🏻

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Spandan Sehgal •

Amazing code snippet.. thanks for telling.

You just saved a lot of time ⏲️ 😌

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Mads Stoumann •

👍🏻

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Slow Coder Sloth •

I love it.

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Mads Stoumann •

👍🏻

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Ganesh Patil •

This is something I'm for, Thanks for sharing! 🚀

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Mads Stoumann •

👍🏻

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ruthmoog •

Great tips, this was exactly what I've been looking for! 👏

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Mads Stoumann •

👍🏻

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Bart •

If statement missing here:

window.matchMedia('(prefers-color-scheme: dark)').matches)) {
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