This is an example of splitLayoutPanel. This type of User Interface is very useful when you want to make navigation, and based on the navigation link, other information are displayed. You can see a usage of Split Layout panel on Android Developer reference page.

function doGet() {

  var app = UiApp.createApplication();

//Create Split layou panel

  var sPanel = app.createSplitLayoutPanel();

//Add west component

  sPanel.addWest(app.createLabel('Navigation'), 100);

//add north compaonent

  sPanel.addNorth(app.createLabel('List goes here'), 200);

  sPanel.add(app.createLabel('detail goes here'));

//define width & height of the split layout panel

  sPanel.setHeight('100%').setWidth('100%');

//Add the splitLayoutPanel to the application

  app.add(sPanel);

  return app;

}