var NN4 = document.layers? true : false;

function findObject(id){
  // If the standard function is available we use it
  if(NN4) return document.layers[id];
  if(document.getElementById) return document.getElementById(id);
  return document.all[id];
}

function switchLayer(name){
	hideAll();
        var property = NN4? "visibility" : "style.visibility";
	var value = NN4? "'show'" : "'visible'";
	eval("findObject(name)." + property + " = " + value + ";");
}

function hideAll(){
  var property = NN4? "visibility" : "style.visibility";
  eval("findObject('about')." + property + " = 'hidden';");
  eval("findObject('psychotherapy')." + property + " = 'hidden';");
  eval("findObject('classes')." + property + " = 'hidden';");
  eval("findObject('yoga')." + property + " = 'hidden';");
  eval("findObject('staff')." + property + " = 'hidden';");
  eval("findObject('information')." + property + " = 'hidden';");
}