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                <!DOCTYPE html>

<script src=""></script>

 var copy = function(){
  var txt = document.getElementById('txt');
  var cont = document.getElementById('container');
  cont.innerHTML = txt.value;

  .btn{border:2px solid black;border-radius}  
    border:2px dotted #777777;
<b>Example showing "bug" in Internet Explorer.</b><BR><BR>

When the content within the textarea is copied into a container by Javascript in Internet Explorer, the (max-width:xx) media query will activate even though the browser width is wider than the filter. Once the browser is adjusted slightly, it reverts to the inactive state.<BR><BR>

<button id="btn" onclick="copy()">Copy textarea HTML to container</button><BR><BR>
When the button is clicked, you will see "Replaced" with a yellow background in Internet Explorer, but blue in other browsers.<BR>

<div id="container">To be replaced...</div><BR><BR>

  Textarea (feel free to edit this below):<BR>    
  <textarea id="txt" cols=80 rows=20>
      background-color: blue;
    @media screen and (max-width:450px){
        background-color: yellow;

  <div class="foo"><input type="radio" checked> Replaced</div>