escape text for inclusion by innerHTML as one handy fully namespaced function

escapeHtml.js

var escapeHTML = (function() {
  var regexp = /[<>&'"\/]/g
    , replacements =
      { '&': '&amp;'
      , '<': '&lt;'
      , '>': '&gt;'
      , '/': '&#x2F;'
      , '"': '&quot;'
      , "'": '&#39;'
      }
    , replacer = function(match) {
        return replacements[match]
      }
  return function(string) {
    return String(string).replace(regexp, replacer)
  }
})()

Have a look at http://js-quasis-libraries-and-repl.googlecode.com/svn/trunk/safetemplate.html first. All simple approaches for HTML-escaping come with a lot of problems.