``` <form > <div class="form-group has-success has-feedback"> <div class="input-group"> <span class="input-group-addon">@</span> <input type="text" class="form-control" id="user"> </div> <span class="glyphicon glyphicon-ok form-control-feedback"></span> </div> </form> ``` ``` .input-group .input-group-add .form-control ```