var screenHeight = screen.height;
var screenWidth = screen.width;

function popup(link,name,hauteur,largeur) {
	var posh = (screenHeight/2) - (hauteur/2); 
	var posl = (screenWidth/2) - (largeur/2);
	newwin = window.open(link,name,'height='+hauteur+',width='+largeur+',scrollbars=no,resizable=yes,directories=no,status=no,top='+posh+',left='+posl);
}