ef1"></div>
  <div id="ref2"></div>
  <div id="test"></div>
  <button>Start</button>
  <script>
    (function() {
      var button = document.querySelector("button"),
          test = document.querySelector("#test"),
          ref1 = document.querySelector("#ref1"),
          ref2 = document.querySelector("#ref2")
      button.addEventListener("click", function(evt) {
        test.setAttribute("style", "width: 300px;");
        ref1.setAttribute("style", "width: 300px;");
        ref2.setAttribute("style", 