javascript add class step by step in loop.

<script src="http://code.jquery.com/jquery-latest.min.js" type="text/javascript"></script>
<script>
$(function () {
  var $anchors = $('.anchor');

  (function _loop(idx) {
    $anchors.removeClass('highlight').eq(idx).addClass('highlight');
    setTimeout(function () {
      _loop((idx + 1) % $anchors.length);
    }, 2000);
  }(0));
});
</script>
<style>
.highlight{
color:#FF0000;
font-size:24px;
}
</style>
<a class="anchor">A</a>
<a class="anchor">B</a>
<a class="anchor">C</a>
<a class="anchor">D</a>
<a class="anchor">E</a>
<a class="anchor">F</a>
<a class="anchor">G</a>