mobile logo

responsive indicator line with tab and content

Solution:

You can do that:

 

function select(nb) {
  $("a").removeClass('underline');
  $("#" + nb).addClass('underline')
}
.underline {
  text-decoration: underline;
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<a id="1" onclick="select('1')">1</a>
<a id="2" onclick="select('2')">2</a>
<a id="3" onclick="select('3')">3</a>
<a id="4" onclick="select('4')">4</a>