countblock = 7;
currentblock = 2;

function hidecurrentblock()
{
  document.getElementById('main_div_'+currentblock).className='maindivhide';
  document.getElementById('v'+currentblock).className='v0';
}

function showcurrentblock()
{
  document.getElementById('main_div_'+currentblock).className='maindivshow';
  document.getElementById('v'+currentblock).className='v'+currentblock;
}

function leftmoving()
{
  hidecurrentblock();
  currentblock = currentblock - 1;
  if(currentblock<1)
  {
   currentblock = countblock;
  }
  showcurrentblock();
}

function rightmoving()
{
  hidecurrentblock();
  currentblock = currentblock + 1;
  if(currentblock>countblock)
  {
   currentblock = 1;
  }
  showcurrentblock();
}

function setto(number)
{
  hidecurrentblock();
  currentblock = number;
  showcurrentblock();
}