Detect System Theme Preference Change Using JavaScript
JavaScript and CSS allow users to detect the user theme preference with CSS' prefers-color-scheme media query. It's standard these days to use that preference to show the dark or light theme on a given website. But what if the user changes their preference while using your app?
To detect a system theme preference change using JavaScript, you need to combine matchMedia, prefers-color-scheme, and an event listener:
window.matchMedia('(prefers-color-scheme: dark)')
.addEventListener('change',({ matches }) => {
if (matches) {
console.log("change to dark mode!")
} else {
console.log("change to light mode!")
}
})
The change event of the matchMedia API notifies you when the system preference changes. You can use this event to automatically update the site's display in real time.
I love that this API allows detecting user preference on a system level. Catering to user needs is an important part of creating a great web experience!
![Designing for Simplicity]()
Before we get started, it's worth me spending a brief moment introducing myself to you. My name is Mark (or @integralist if Twitter happens to be your communication tool of choice) and I currently work for BBC News in London England as a principal engineer/tech...
![Facebook Open Graph META Tags]()
It's no secret that Facebook has become a major traffic driver for all types of websites. Nowadays even large corporations steer consumers toward their Facebook pages instead of the corporate websites directly. And of course there are Facebook "Like" and "Recommend" widgets on every website. One...
![Introducing MooTools HeatMap]()
It's often interesting to think about where on a given element, whether it be the page, an image, or a static DIV, your users are clicking. With that curiosity in mind, I've created HeatMap: a MooTools class that allows you to detect, load, save, and...
![Save Web Form Content Using Control + S]()
We've all used word processing applications like Microsoft Word and if there's one thing they've taught you it's that you need to save every few seconds in anticipation of the inevitable crash. WordPress has mimicked this functionality within their WYSIWYG editor and I use it...
