JS+JavaBean判断管理员增删改的操作权限

<%
     String username = (String)session.getAttribute("username");
     UserService userService=new UserServiceImpl();
     System.out.println("username=============>"+username);
     int role = userService.getRoleByUsername(username);
     System.out.println("role=============>"+role);
     if(role==0){
  %>
  <script type="text/javascript">
          function add(){
              window.location="<%=request.getContextPath() %>/jsp/billAdd.jsp";
          }
  </script>
  
  <%}else{ %>
      <script type="text/javascript">
          function add(){
              alert("你不是管理员，没有新增的权限！");
  }
  </script>
  <%} %>

<em><input value="添加账单" class="input-button" onclick="add();" type="button">