String.prototype.stripTags = String.prototype.stripTags.wrap(
  function(proceed, allowTags) {
    if (allowTags) {
      if (Object.isString(allowTags)) allowTags = $w(allowTags)
      this.gsub(/(<\/?\s*)([^\s>]+)(\s[^>]*)?>/, function(match) {
        if (allowTags.include(match[2].toLowerCase()))
          return match[1] + match[2] + match[3] + '>'
      })
    } else {
      // proceed using the original function
      return proceed();
    }
  });