[рони]

<script>
window.addEventListener('DOMContentLoaded', function() {
   var input = document.querySelector('.test');
    input.addEventListener('input', function(e){
        this.classList[ this.value?'add':'remove']('green');
    });
   });
</script>
  <style type="text/css">
     .green{
        border: 5px solid #008000;
     }

  </style>
<input id="my_input" class="test">