title: open and play a scene in Unity3d
body: <p>I have done a project with many scenes in Unity3D.
  In the first scene there are buttons, each of them will play a scene when clicked.
  For example, if the player clicks the button “Show the balloon”, then the scene called Balloon (which contains a balloon object and its animation) will be opened.</p>
  
  <p>How can I do it using JavaScript code?</p>