function open_newsletter(){
	var h=200;
	var l=420;
	var hauteur=Math.round((screen.availHeight-h)/2); 
	var largeur=Math.round((screen.availWidth-l)/2); 
	window.open("newsletter.html", null, "width="+l+", height="+h+", top="+hauteur+", left="+largeur+", status=no, resizable=no, toolbar=no, menubar=no, scrollbars=no")
}