为啥运行到这里时document.getElementById("indicator").style.display="block"显示是缺少对象的？ _Ajax

为什么运行到这里时document.getElementById("indicator").style.display="block";显示是缺少对象的？？

本帖最后由 showbo 于 2012-10-24 21:19:18 编辑

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>

<%

String path = request.getContextPath();

%>

<!DOCTYPE HTML PUBLIC"-//W3C//DTC HTML 4.01 Transitional//EN">

<html>

<head>

          <script type='text/javascript' src='<%=path %>/dwr/interface/loginService.js'></script>

          <script type='text/javascript' src='<%=path %>/dwr/engine.js'></script>

          <script type='text/javascript' src='<%=path %>/dwr/util.js'></script>

        

          <script language="javascript">

          function check1()

          {

               if(document.ThisForm.userName.value=="")

               {

                    alert("请输入用户名");

                    document.ThisForm.userName.focus();

                    return false;

               }

               if(document.ThisForm.userPw.value="")

               {

                alert("请输入密码");

                return false;

                }

                document.getElementById("indicator").style.display="block";

                loginService.login(document.ThisForm.userName.value,document.ThisForm.userPw.value,0,callback);

                }

                function callback(data)

                {

                     document.getElementById("indicator").style.display="none";

                 if(data=="no")

                {

                     alert("用户名或密码错误");

                }

为啥 运行到这里时document.getElementById("indicator").style.display="block"显示是缺少对象的 ？

为啥运行到这里时document.getElementById("indicator").style.display="block"显示是缺少对象的？