Leverage the browser to escape or unescape HTML via javascript

gistfile1.js

function escapeHtml(str) {
  var div = document.createElement('div');
  div.appendChild(document.createTextNode(str));
  return div.innerHTML;
};
function unescapeHtml(escapedStr) {
  var div = document.createElement('div');
  div.innerHTML = escapedStr;
  var child = div.childNodes[0];
  return child ? child.nodeValue : '';
};