function Update () {
  if (Input.GetKey(KeyCode.Home)){
  
   //Home button pressed! write every thing you want to do
  
   }
  if (Input.GetKey(KeyCode.Escape)){
  //Escape button codes
  }
  if(Input.GetKey(KeyCode.Menu)){
                 Application.Quit();
 }
 }

function Update () {
    if (Input.GetKey(KeyCode.Home)){
        // Home button pressed 
        // Write everything you want to do here
    }
    if (Input.GetKey(KeyCode.Escape)){
        // Escape button pressed
    }
    if(Input.GetKey(KeyCode.Menu)){
        Application.Quit();
    }
}