The length read-only property of the StyleSheetList interface returns the number of CSSStyleSheet objects in the collection.

An integer indicating the number of items in the collection.

In the following example, length is printed to the console, and also used in a for loop to print each individual CSSStyleSheet object to the console.

let length = document.styleSheets.length;
console.log(length);

for (let i = 0; i < length; i++) {
  console.log(document.styleSheets[i]);
}