JSFiddle - React, Tailwind, and code Playground

HTML

<div class="tabindex"></div>
<div class="tabindex"></div>
<div class="tabindex"></div>
<div class="tabindex"></div>
<div class="tabindex"></div>

CSS

.tabindex {
    width: 100px;
    height: 50px;
    background-color: green;
    margin: 10px;
}
.tabindex.tabfocus {
    background-color: red;
}

JavaScript

$(window).on('keydown', function(e){
    e.preventDefault();
    var f = $('.tabindex.tabfocus');
    if(e.which != 9) return false;
    if(f.length){
        f.removeClass('tabfocus');
        if(f.next().length){
          f.next().addClass('tabfocus');
        }else{
          $('.tabindex').first().addClass('tabfocus');  
        }
    }else{
        $('.tabindex').first().addClass('tabfocus');
    }
    return false;
});