function open_Centered_window(LaPage, NomPage, Params, Haut, Larg) {
	var H = (screen.height - Haut) / 2 - 50;
	var L = (screen.width - Larg) / 2;
	var xParams = Params + ",height="+Haut+",width="+Larg+",top="+H+",left="+L;
	pop_up = window.open(LaPage,NomPage,xParams);
}