function doGet() {

  var app = UiApp.createApplication();

  

  //Create a penel which will hold all the elements

  var panel = app.createVerticalPanel();

  

  //Create a label, also set a tag to that label. Tag value must be same as the label text

  var label = app.createLabel('This is my Label').setId('myLabel').setTag('This is my Label');

  var button = app.createButton('Submit');

  

  //Create a invisible label which will be visible after submit, 

  //and hold the tag value/label text

  var labelInfo = app.createLabel().setVisible(false).setId('labelInfo');

  

  //Create a handler for the button

  var handler = app.createServerClickHandler('showDates');

  //add the panel as a callback element

  handler.addCallbackElement(panel);

  button.addClickHandler(handler);

  

  //Add all the lements to the panel

  panel.add(label).add(button).add(labelInfo);

  

  //Add the panel to the application

  app.add(panel);

  return app; 

}

//this function will show the dates

function showDates(e){

  

  //get the active aplication

  var app = UiApp.getActiveApplication();

  

  //get the tag value which is equal to the label text

  var labelText = e.parameter.myLabel_tag;

  

  app.getElementById('labelInfo').setText(labelText).setVisible(true);

  

  return app;

}