onclick action instead of url

Module generates URL for each flag
<a href="/flag/flag-name/NID?destination=url" class="use-ajax" rel="nofollow" data-once="ajax">,
but some search engines robots doesnt respect "nofollow" tag, so they gets a lot of 302 responces (kinda 20k hits per 4k nodes).

Is it some ways to use ajax flag onclick event, not url?

BTW, thanks for the great module