function showloginform()
 {
  document.getElementById('niceloginform').style.display = 'block';
  document.getElementById('screen').style.display = 'block';
  document.getElementById('screen').style.height = getyScroll() + 'px';
 }

function hideloginform()
 {
  document.getElementById('niceloginform').style.display = 'none';
  document.getElementById('screen').style.display = 'none';
 }