var DW_PAGEMASK_CONFIG = {
  'element': 'page_mask',
  'method': 'display'
};

function set_mask_visibility (visible) {
  var mask = document.getElementById(DW_PAGEMASK_CONFIG.element);
  
  switch (DW_PAGEMASK_CONFIG.method) {
    case 'visibility':
      mask.style.visibility = visible?'visible':'hidden';
      break;

    case 'display':
      mask.style.display = visible?'block':'none';
      break;
      
    default:
      alert("Don't know what to do with method '"+DW_PAGEMASK_CONFIG.method+"'.");
  };
  
  return;
}

function pagemask_on () {
  return set_mask_visibility(true);
}

function pagemask_off () {
  return set_mask_visibility(false);
}