<div class="container" id="container">
  <div class="item">1</div>
  <div class="item">2</div>
  <div class="item">3</div>
  <div class="item">4</div>
  <div class="item">5</div>
</div>
<div class="controls">
  <input type="radio" name="flex-direction" id="row" 
         onclick="
                  var container=document.getElementById('container'); 
                  container.style.WebkitFlexDirection = 'row'; 
                  container.style.flexDirection = 'row'; 
                  " checked>
  <label for="row">flex-direction: row;</label>
  <br>
  <input type="radio" name="flex-direction" id="row-reverse" 
         onclick="
                  var container=document.getElementById('container'); 
                  container.style.WebkitFlexDirection = 'row-reverse'; 
                  container.style.flexDirection = 'row-reverse'; 
                  ">
  <label for="row-reverse">flex-direction: row-reverse;</label>
  <br>
  <input type="radio" name="flex-direction" id="column" 
         onclick="
                  var container=document.getElementById('container'); 
                  container.style.WebkitFlexDirection = 'column'; 
                  container.style.flexDirection = 'column'; 
                  ">
  <label for="column">flex-direction: column;</label>
  <br>
  <input type="radio" name="flex-direction" id="column-reverse" 
         onclick="
                  var container=document.getElementById('container'); 
                  container.style.WebkitFlexDirection = 'column-reverse'; 
                  container.style.flexDirection = 'column-reverse'; 
                  ">
  <label for="column-reverse">flex-direction: column-reverse;</label>
</div>
body {
    background-color: #F5F5F5;
    color: #555;
    font-size: 1.1em;
    font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
}

hr {
    margin: 50px 0;
}

.container {
    margin: 150px auto;
    max-width: 800px;
    padding: 20px;
    -webkit-display: -webkit-box;
    -webkit-display: -webkit-flex;
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    background-color: #594255;
}

.item {
    background-color: #fff;
    width: 100px;
    height: 100px;
    margin: 2px;
    text-align: center;
    line-height: 100px;
    font-weight: bold;
    font-family: sans-serif;
    font-size: 5em;
    color: #594255;
}

.controls {
    background-color: white;
    width: 300px;
    padding: 20px;
    line-height: 150%;
    position: fixed;
    top: 0;
    right: 0;
    border: 1px solid #ddd;
}