js计算阶乘和新打开一个窗口

<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%> 
  <%
String path= request.getContextPath();
String basePath=request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>