function change_option(number,index){
 for (var i = 1; i <= number; i++) {
      document.getElementById('current' + i).className = 'title3d';
      document.getElementById('content' + i).style.display = 'none';
 }
  document.getElementById('current' + index).className = 'title1c';
  document.getElementById('content' + index).style.display = 'block';
}