function switchTab (num, tab,tabc) {
   var c = num == 1 ? 2 : 1;
   
   //active tab
   var tabid = document.getElementById(tab+num);
   tabid.className = 'active';
   //show content
   document.getElementById(tabc+num).style.display = '';
   
   //hide tab 
   var tabidH = document.getElementById(tab+c);
   tabidH.className = '';
   var ctabidH = document.getElementById(tabc+c).style.display = 'none';	
}