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!
![39 Shirts – Leaving Mozilla]()
In 2001 I had just graduated from a small town high school and headed off to a small town college. I found myself in the quaint computer lab where the substandard computers featured two browsers: Internet Explorer and Mozilla. It was this lab where I fell...
![How I Stopped WordPress Comment Spam]()
I love almost every part of being a tech blogger: learning, preaching, bantering, researching. The one part about blogging that I absolutely loathe: dealing with SPAM comments. For the past two years, my blog has registered 8,000+ SPAM comments per day. PER DAY. Bloating my database...
![dat.gui: Exceptional JavaScript Interface Controller]()
We all love trusted JavaScript frameworks like MooTools, jQuery, and Dojo, but there's a big push toward using focused micro-frameworks for smaller purposes. Of course, there are positives and negatives to using them. Positives include smaller JS footprint (especially good for mobile) and less cruft, negatives...
![Digg-Style Dynamic Share Widget Using MooTools]()
I've always seen Digg as a very progressive website. Digg uses experimental, ajaxified methods for comments and mission-critical functions. One nice touch Digg has added to their website is their hover share widget. Here's how to implement that functionality on your site...