window.onload = addBanner ;

function addBanner()
  {
  var n = Math.floor( Math.random() * 3 ) ;
  var html ;

  if( n == 0 )
    {
    html = "<a href='/officespace.shtml'><img src='/banners/0.jpg' border=0></a>" ;
    }
  else if( n == 1 )
    {
    html = "<a href='/labspace.shtml'><img src='/banners/1.jpg' border=0></a>" ;
    }
  else
    {
    html = "<a href='/conference.shtml'><img src='/banners/2.jpg' border=0></a>" ;
    }

  document.getElementById('banner').innerHTML = html ;
  document.getElementById('banner').style.display = "block" ;
  }