HTMLFormElement: rel property

The rel property of the HTMLFormElement interface reflects the rel attribute. It is a string containing what kinds of links the HTML <form> element creates, as a space-separated list of enumerated values.

To retrieve the value as an array of tokens, use HTMLFormElement.relList.

const form = document.querySelector("form");
console.log(form.rel);

form.rel = "noopener noreferrer";