function showLoginPopup()
{
  document.getElementById('popup_layer').style.display = 'block';
  document.getElementById('login_blox_pre').style.display = 'block';  
  document.getElementById('login_blox').style.display = 'block';
}

function hideLoginPopup()
{
  document.getElementById('popup_layer').style.display = 'none';
  document.getElementById('login_blox_pre').style.display = 'none';  
  document.getElementById('login_blox').style.display = 'none';
}