var oldStatesData = new Array();
var oldStatesAct = new Array();

function ka_hideBtn(btnId){
  if (!oldStatesAct[btnId]){
    var btn = document.getElementById(btnId);
    
    oldStatesData[btnId]=btn.className;
    oldStatesAct[btnId]=true;
    
    btn.className = btn.className.replace('active', '');
  }
  
  return true;
}
function ka_restoreBtn(btnId){
  if (oldStatesAct[btnId]){    
    var btn = document.getElementById(btnId);
    btn.className=oldStatesData[btnId];
    oldStatesAct[btnId]=false;
  }
  
  return true;
}