code: function _Browser_visibilityInfo()
  {
  	return (typeof __VirtualDom_doc.hidden !== 'undefined')
  		? { __$hidden: 'hidden', __$change: 'visibilitychange' }
  		:
  	(typeof __VirtualDom_doc.mozHidden !== 'undefined')
  		? { __$hidden: 'mozHidden', __$change: 'mozvisibilitychange' }
  		:
  	(typeof __VirtualDom_doc.msHidden !== 'undefined')
  		? { __$hidden: 'msHidden', __$change: 'msvisibilitychange' }
  		:
  	(typeof __VirtualDom_doc.webkitHidden !== 'undefined')
  		? { __$hidden: 'webkitHidden', __$change: 'webkitvisibilitychange' }
  		: { __$hidden: 'hidden', __$change: 'visibilitychange' };
  }
docs: PAGE VISIBILITY