function show(id,num){

  if(num == '1') {

    document.getElementById(id + 'on').className = 'active';

    document.getElementById(id).className = 'off';

  }

  else if(num == '2') {

    document.getElementById(id).className = 'active';

    document.getElementById(id + 'on').className = 'off';

  }

  else {

    return false;

  }

}