code: function setUpShowCheckBox(element, key) {
      var value = localStorage.getItem(key)
      if (null == value)
          value = true
      else
          value = (value == "true")
  
      element.checked    = value
      element.storageKey = key
  
      element.addEventListener("click", el_showCheckBoxClicked, false)
  }
docs: -----------------------------------------------------------------------------