function secBoard(n) 
{ 
var d=document.getElementById('zd_sub-'+n);
var v=document.getElementById('zd-'+n);
  for (var j=0;j<7;j++)
    {
      if(j==n) {v.className="sub2";d.style.display='';}
      else {document.getElementById('zd-'+j).className="sub1";document.getElementById('zd_sub-'+j).style.display='none';}
    }

} 

function secBoardk(n) 
{ 
var d=document.getElementById('kf_sub-'+n);
var v=document.getElementById('kf-'+n);
  for (var j=0;j<7;j++)
    {
      if(j==n) {v.className="sub2";d.style.display='';}
      else {document.getElementById('kf-'+j).className="sub1";document.getElementById('kf_sub-'+j).style.display='none';}
    }

} 

function sec(n) 
{ 
var d=document.getElementById('ht_sub-'+n);
var v=document.getElementById('ht-'+n);
  for (var j=0;j<2;j++)
    {
      if(j==n) {v.className="sub2";d.style.display='';}
      else {document.getElementById('ht-'+j).className="sub1";document.getElementById('ht_sub-'+j).style.display='none';}
    }

} 


function answer(n) 
{ 
var d=document.getElementById('ans_sub-'+n);
var v=document.getElementById('ans-'+n);
  for (var j=0;j<2;j++)
    {
      if(j==n) {v.className="sub2";d.style.display='';}
      else {document.getElementById('ans-'+j).className="sub1";document.getElementById('ans_sub-'+j).style.display='none';}
    }

}