<div class="controls">
<select id="alignMe">
  <option value="stretch">stretch</option>
  <option value="flex-start">flex-start</option>
  <option value="flex-end">flex-end</option>
  <option value="center">center</option>
  <option value="space-around">space-around</option>
  <option value="space-between">space-between</option>
  <option value="space-evenly">space-evenly</option>
</select>

</div>

<div class="container" id="container">
  <div class="item">One</div>
  <div class="item">Two Two</div>
  <div class="item">Three Three Three</div>
  <div class="item">Four Four Four Four</div>
</div>

body {
  padding: 20px;
  font: 1em Helvetica Neue, Helvetica, Arial, sans-serif;
}

* {box-sizing: border-box;}

p {
  margin: 0 0 1em 0;
}

.container {  
  border: 5px solid rgb(111,41,97);
  border-radius: .5em;
  padding: 10px;
  max-width: 400px;
  height: 60vh;
  display: flex;
  flex-wrap: wrap;
}

.item {
  padding: 10px;
  background-color: rgba(111,41,97,.3);
  border: 2px solid rgba(111,41,97,.5);
}

.controls {
  background-color: rgba(0,0,0,.1);
  padding: 10px;
  border-radius: .5em;
  border: 1px solid rgba(0,0,0,.2);
  margin: 0 0 2em 0
}

.controls select {
  font-size: .9em;
}

var align = document.getElementById("alignMe");
alignMe.addEventListener("change", function (evt) {
  document.getElementById("container").style.alignContent = evt.target.value;
});