function Ouvrir_Popup(page,largeur,hauteur,options)
{
    var top=(screen.height-hauteur)/2;
    var left=(screen.width-largeur)/2;
    window.open(page,"","top="+top+",left="+left+",width="+largeur+",height="+hauteur+","+options);
}

//Fonction pour afficher l'aide
function Cover(bottom, top, ignoreSize) 
{
  var location = Sys.UI.DomElement.getLocation(bottom);
  top.style.position = 'absolute';
  top.style.top = location.y + 'px';
  top.style.left = location.x + 'px';
  if (!ignoreSize) 
  {
     top.style.height = bottom.offsetHeight + 'px';
     top.style.width = bottom.offsetWidth + 'px';
  }
}