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              <div>Footer <strong>em</strong> width: <span id="em-width">tbd</span></div>
<div>Footer <strong>rem</strong> width: <span id="rem-width">tbd</span></div>

<footer id="footer">
  <p>Learn more about <a href="http://www.matanich.com/2013/06/24/em-values-javascript/">getEmPixels()</a>. Brought to you by <a href="http://matanich.com">Tyson Matanich</a></p>
              body {
  font-size: 100%;
  font-family: sans-serif;

h4 {
  margin: 0;

#rem-width {
  font-weight: bold;
  color: #36800D;

footer {
  /*width: 400px;*/
  font-size: 0.875em;
  border-top: 1px solid #ddd;
  margin-top: 1em;
  padding-top: 0.75em;
              var footer = document.getElementById('footer');
var resultEm = document.getElementById('em-width');
var resultRem = document.getElementById('rem-width');

function updateResults() {
  // Get the width of 1em for the footer element
  var footerEm = getEmPixels(footer);
  // Get the width of 1rem
  var rem = getEmPixels();
  // Do some division to convert footer width to ems and rems
  var footerEmWidth = footer.clientWidth / footerEm;
  var footerRemWidth = footer.clientWidth / rem;
  // Update the values
  resultEm.innerHTML = footerEmWidth + "em";
  resultRem.innerHTML = footerRemWidth + "rem";

// Update the results on load, dom ready, and resize
if (window.addEventListener) {
  window.addEventListener("resize", updateResults, false);
  window.addEventListener("DOMContentLoaded", updateResults, false);
  window.addEventListener("load", updateResults, false);
} else if (window.attachEvent) {
  window.attachEvent("onresize", updateResults);
  window.attachEvent("onload", updateResults);
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