How to make an analogue of nofollow for a button?

Question

HTML

Hello! In html , the rel=nofollow attribute is used
to prohibit the indexing of a link in a tag . If a button ( ) is placed on the page and a click on it is processed by JS, redirecting to the page with the command<a>
<button>

$( ".button" ).on( "click", function() {
window.open("http://externalSite.ru/", '_blank')
})

What if I want to block this link from being indexed by search engines.
And in general, do search engines consider a button with such a handler to be a link?

Answer 1

What if I want to block this link from being indexed by search engines.
It won't be indexed anyway.