window.open(url, "_black" , spec)

var url = "${request.contextPath}/test/openWindow.action?number="+number;
var spec = "scrollbars=yes,toolbar=no,menubar=no,location=no,status=yes,resizable=yes,left=400,top=200,width=400"  + ",height=150";
var oNewWindow = window.open(url, "_black" , spec);