JSFiddle - React, Tailwind, and code Playground

HTML

<a href="#">Cos tam</a>
<a href="google.pl">Google</a>
<a href="#">Cos tam</a>
<a href="google.pl">Google</a>
<a href="#">Cos tam</a>
<a href="google.pl">Google</a>
<a href="#">Cos tam</a>
<a href="google.pl">Google</a>

CSS

.niema { color: red; }

JavaScript

var linki = $("a"),
    link;

for (var i = 0, l = linki.length; i < l; i++) {
    link = $(linki[i]);
    
    if (link.attr("href") === "#") {
        link.addClass("niema");        
    }
}