Document: preferredStyleSheetSet property - Web APIs | MDN
Value
The author's preferred style sheet set. This is determined from the order of style sheet declarations and the
Default-Style HTTP header.
If there isn't a preferred style sheet set defined by the author, the empty string ("") is returned.
Examples
js
if (document.preferredStyleSheetSet) {
console.log(
`The preferred style sheet set is: ${document.preferredStyleSheetSet}`,
);
} else {
console.log("There is no preferred style sheet.");
}