The selectorText property of the CSSPageRule interface gets and sets the selectors associated with the CSSPageRule.
A string.
The stylesheet includes two @page rules. The selectorText property will return the literal selector text of :first as a string.
@page {
margin: 1cm;
}
@page :first {
margin: 2cm;
}const myRules = document.styleSheets[0].cssRules; // Two myRules
console.log(myRules[1].selectorText); // ":first"