function preloader(id1, id2)
{
obj1 = document.getElementById(id1);
obj2 = document.getElementById(id2);

if(obj1.style.display == '')
{
  obj1.style.display = 'none';
  obj2.style.display = '';
  
}
else
{
  obj1.style.display = '';
  obj2.style.display = 'none';
}
}