var aW = 800, aH = 600;

if( document.all || document.layers )
{
  aW = screen.availWidth;
  aH = screen.availHeight;
}
else
{
  aW = screen.width;
  aH = screen.height;
}

var popW = 769;
var popH = 585;
var popIpxW = 604;
var popIpxH = 445;

var titlebarHeight = 30; // et bordures!
var toolbarHeight = 40; // etimation de la taille maximum
var menubarHeight = 25;
var scrollbarWidth = 16;
var scrollbarHeight = 0;

var toolbarOption = 'yes';
var menubarOption = 'yes';
var scrollbarOption = 'no';

var leftPos = parseInt( ( aW-popW )/2 )
var topPos = parseInt( ( aH-popH-1.5*titlebarHeight-1.5*toolbarHeight-1.5*menubarHeight )/2 );
if( topPos < 0 ){ topPos = 0; }

var leftIpxPos = parseInt( ( aW-popIpxW )/2 )
var topIpxPos = parseInt( ( aH-popIpxH-1.5*titlebarHeight-1.5*toolbarHeight-1.5*menubarHeight )/2 );
if( topIpxPos < 0 ){ topIpxPos = 0; }


var minimumHeight = 650;

if( aH < minimumHeight  )
{
  if( navigator.appVersion.indexOf('Mac') != -1 ){ scrollbarWidth = 25; }
  if( navigator.appName.indexOf('Microsoft') != -1 ){ scrollbarHeight=16; scrollbarWidth = 0; }
  popH = aH-titlebarHeight-scrollbarHeight-toolbarHeight; 
  popW += scrollbarWidth;
  topPos = 0;
  leftPos = 0;

  popIpxH = aH-titlebarHeight-scrollbarHeight-toolbarHeight; 
  popIpxW += scrollbarWidth;
  topPos = 0;
  leftPos = 0;

  menubarOption = 'no';
  scrollbarOption = 'yes';
}