function check_spares() {
  radio = 0;

  for (i=0;i<document.buy.tech_centre.length;i++)
  {
    if ((document.buy.tech_centre[i].checked)==true)
       radio = 1;
  }

  if (radio==0)
  {
     alert('Выберите автосалон пожалуйста!');
     return false;
  }

  var arr_check = [true, true, true, true];

  if (document.forms.spares.car_type.value == 'Не выбрано') {
  document.all['err1'].style.visibility='visible'; 
  arr_check[0] = false;
  }
  else {
  document.all['err1'].style.visibility='hidden';
  }
  if (document.forms.spares.vin_code.value == '') {
  document.all['err2'].style.visibility='visible'; 
  arr_check[1] = false;
  }
  else {
  document.all['err2'].style.visibility='hidden';
  }
  if (document.forms.spares.guarantee.value == '') {
  document.all['err3'].style.visibility='visible'; 
  arr_check[2] = false;
  }
  else {
  document.all['err3'].style.visibility='hidden';
  }
  if (document.forms.spares.tech_centre.value == '') {
  document.all['err4'].style.visibility='visible';
  arr_check[3] = false;
  } 
  else {
  document.all['err4'].style.visibility='hidden';
  }
  indicator = true;
  j = 0;
  while (indicator == true) 
  {
      for (i=0;i<arr_check.length;i++) 
      {
        if (arr_check[i] == true) 
        {
          indicator = true;
        }
        else 
        {
          indicator = false;
          return false;
        }
      }
    j = j + 1;
    if (j == arr_check.length) 
    {
     return true;
    }      
  }
return false;
}