function open_window(page, hauteur, largeur){
	var height = hauteur + 20;
	var width = largeur + 20;
	var H = (screen.height - hauteur) / 2;
	var L = (screen.width - largeur) / 2;
	pop_up = window.open(page, '', "toolbar=no,location=no,status=no,menubar=no,scrollbars=no,resizable=no,height="+height+",width="+width+",top="+H+",left="+L);
}