js calculates factorial and opens a new window

<%@ 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+"/"; 
   %>