Is functional js link broken?

Question

Search Engine Optimization

Good afternoon, when analyzing the links, a lot of broken ones were revealed, while these links were not in the visibility area on the page, however, in the source code of the page, these links are present a href="123", they probably perform some kind of ajax \ js function, whether Does the search engine recognize such links as broken? Do search engines consider such links broken and would adding rel="nofollow" to such links help.
webasyst engine Thanks
in advance!