function showTab(id)
{
   DelayTimer();
   var offer = document.getElementById('offer');
   var tabs = offer.getElementsByTagName('div');
 
   for(var i=0;i<tabs.length;i++)
   {
      tabs[i].style.display = 'none';
      document.getElementById('lnk'+(i+1)).className = '';
   }

   document.getElementById('tab'+id).style.display = 'block';
   document.getElementById('lnk'+id).className = 'active';
}

function SetActiveTab(id)
{
   var offer = document.getElementById('offer');
   var tabs = offer.getElementsByTagName('div');
 
   for(var i=0;i<tabs.length;i++)
   {
      tabs[i].style.display = 'none';
      document.getElementById('lnk'+(i+1)).className = '';
   }

   if(id>=tabs.length)
      id=0;
   
   tabs[id].style.display = 'block';
   document.getElementById('lnk'+(id+1)).className = 'active';
}

function GetActiveTab()
{
   var offer = document.getElementById('offer');
   var tabs = offer.getElementsByTagName('div');
 
   for(var i=0;i<tabs.length;i++)
   {
      if(tabs[i].style.display == 'block')
         return i;
   }

   return 0;
}

var timerID         = 0;
var refreshInterval = 3;

function UpdateTimer()
{
   if(timerID)
      clearTimeout(timerID);

   var id = GetActiveTab();
   id++;
   SetActiveTab(id);
   
   timerID = setTimeout("UpdateTimer()", refreshInterval * 1000);
}

function DelayTimer()
{
   if(timerID)
      clearTimeout(timerID);

   var id = GetActiveTab();
   id++;
   SetActiveTab(id);
   
   timerID = setTimeout("UpdateTimer()", 10 * 1000);
}

function StartTimer()
{
   timerID  = setTimeout("UpdateTimer()", refreshInterval * 1000);
}

function StopTimer()
{
   if(timerID)
      clearTimeout(timerID);

   timerID  = 0;
}

SetActiveTab(0);
StartTimer();