web api overview
User Preferences API
Limited availability
The User Preferences API allows page authors to programmatically override user preference-related media query settings.
Concepts and Usage
Supporting user agents define values for the CSS media queries prefers-color-scheme, prefers-contrast, prefers-reduced-motion, prefers-reduced-transparency, and prefers-reduced-data. The PreferenceManager object provides programmatic access to these preferences, allowing page authors to listen for preference changes and override them.
Examples
Dark Mode Toggle
The following code implements a minimal dark mode toggle.
HTML
The HTML features a form containing three radio buttons. These radio buttons set the color-scheme field to either system, light, or dark.
<!doctype html>
<html lang="en-US">
<head>
<meta name="color-scheme" content="light dark" />
</head>
<body>
<form>
<label>
<input type="radio" name="color-scheme" value="light" />
Light
</label>
<label>
<input type="radio" name="color-scheme" value="dark" />
Dark
</label>
</form>
</body>
</html>
JavaScript
The JavaScript registers change event listeners for all elements named color-scheme. If the value is system, the handler clears the color scheme override. Otherwise, it requests a color scheme override with the value of the input element.
if (navigator.preferences) {
const inputs = {
light: document.querySelector('[name="color-scheme"][value="light"]'),
dark: document.querySelector('[name="color-scheme"][value="dark"]'),
};
inputs[navigator.preferences.colorScheme.value].checked = true;
inputs.light.addEventListener("change", () => {
navigator.preferences.colorScheme.requestOverride("light");
});
inputs.dark.addEventListener("change", () => {
navigator.preferences.colorScheme.requestOverride("dark");
});
navigator.preferences.colorScheme.addEventListener("change", () => {
inputs[navigator.preferences.colorScheme.value].checked = true;
});
} else {
document.body.append(
"Your browser doesn’t support the navigator.preferences API",
);
}
Result
body {
font-family: system-ui, sans-serif;
}
label {
display: block;
margin: 0.5em 0;
}