function open_stf() {
    var w = 800, h = 700;
    var left = (screen.width - w) / 2;
	var _top = (screen.height - h) / 2;
	var	opt = 'toolbar=yes,resizable=yes,menubar=yes,width='+w+',height='+h+',scrollbars=yes,location=no,titlebar=yes,directories=no,screenX='+_top+',screenY='+left+',top='+_top+',left='+left;
	window.open('/send-to-friend', 'stf', opt);
}