1. I wrote a demo.html using requirejs. When the page is loaded for the first time, it can be displayed normally. Then an error starts to appear when the page is refreshed. Although the page is still displayed normally, I don't understand why this is happening.
2. My other 999.html file (which is in the same directory as demo.html, but has more page content, and the rest is not much different from the html in 1) keeps reporting errors, or displays require is not define Either Script error for "jquery" or $ is not defined is displayed. Why is this and how should it be changed?
The code is as follows:
demo.html：
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
<script src="resource/require.js"></script>
<script src="resource/main.js"></script>
</head>
<body>
<script type="text/javascript">
require(['jquery','weui'],function($){
$('body').css('background','red');
});
</script>
</body>
</html>main.js：
require.config({
baseUrl:'resource/app',
paths:{
'jquery':'../lib/jquery-3.2.0.min',
'zepto':'../lib/zepto.min',
'css':'../lib/css.min',
'weui':'../lib/jquery-weui.min',
'cookie':'../lib/jquery.cookie',
'swiper':'../lib/swiper'
}
});Error message: 
<!DOCTYPE html><html>
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width,initial-scale=1,minimum-scale=1,maximum-scale=1,user-scalable=no" />
<title></title>
<link rel="stylesheet" type="text/css" href="resource/css/weui.css" />
<link rel="stylesheet" type="text/css" href="resource/css/jquery-weui.min.css" />
<link rel="stylesheet" type="text/css" href="resource/css/index.css" />
<link rel="stylesheet" type="text/css" href="resource/css/login.css"/>
<link rel="shortcut icon" href="resource/font/cake.ico" />
<script src="resource/require.js" data-main = "resource/main" defer async="true"></script>
</head>
<body ontouchstart>
<!--login section-->
<p id="ologin" class="weui-tab__bd-item" style="height: auto;">
<p class="beforeLogin">
<header>
<p class="head-bg">
</p>
<p class="touxiang">
<img src="img/head/0.png" />
</p>
</header>
<!--登录-->
<section class="adminpage" id="login">
<form action="login.php" method="post" id="loginForm">
<input type="number" value="" placeholder="请输入手机号" name="user" class="phone4log" maxlength="11" />
<input type="password" value="" placeholder="请输入密码（6-16位）" name="psw" id="psw-log" maxlength="16" />
<button type="submit" class="sub" id="loginBut">登录</button>
</form>
<span>没有账号？<a href="#regis">注册</a></span><br />
<span><a href="#forget">忘记密码？</a></span>
</section>
<!--注册-->
<section class="adminpage" id="regis">
<form id="checkphone">
<input type="hidden" name="forwhat" value="forcheck" />
<input type="number" value="" placeholder="请输入手机号" name="user" class="phone4reg vali-input" id="phone4reg" maxlength="11" />
<button type="button" class="vali-but" id="but1" style="color: #fff;background: orange;">点击发送<br />验证码</button>
</form>
<form action="register.php" method="post" id="regisForm">
<input type="hidden" name="forwhat" value="forrig" />
<input type="number" value="" placeholder="请输入验证码" name="validate" id="validate" />
<input type="password" value="" placeholder="设置密码（6-16位）" name="psw" id="psw-reg" maxlength="16" />
<input type="password" value="" placeholder="重新输入密码" name="pswcheck" id="pswcheck" />
<button type="submit" style="color: #fff;background: orange;" class="sub" id="regisBut">注册</button>
</form>
<span>已有账号？<a href="#login">登录</a></span><br />
<span><a href="#forget">忘记密码？</a></span>
</section>
<!--忘记密码-->
<section class="adminpage" id="forget">
<form id="check4forget">
<input type="hidden" name="forwhat" value="forcheck" />
<input type="number" name="findphone" id="findphone" value="" class="vali-input" placeholder="请输入注册的手机号" maxlength="11"/>
<button type="button" class="vali-but" id="but2">点击发送<br />验证码</button>
</form>
<form action="validatePhone.php" method="post" id="forgetForm">
<input type="hidden" name="forwhat" value="forreset" />
<input type="number" value="" placeholder="请输入验证码" name="validate" id="validate4forget" />
<input type="password" value="" placeholder="重新设置密码（6-16位）" name="psw-forget" id="psw-forget" maxlength="16" />
<input type="password" value="" placeholder="重新输入密码" id="pswcheck4forget" maxlength="16"/>
<button type="submit" class="sub" id="reset">重置密码</button>
</form>
<span>已有账号？<a href="#login">登录</a></span><br />
<span>没有账号？<a href="#regis">注册</a></span>
</section>
</p>
<p class="alreadyLogin">
<header>
<p class="head-bg">
<h3></h3>
</p>
<p class="touxiang">
<img src="" />
</p>
</header>
<section>
<p class="weui-cells" style="margin-top: 60px;">
<a href="#" class="weui-cell weui-cell_access">
<p class="weui-cell__bd">
<p>我的收藏</p>
</p>
</a>
<a href="javascript:;" class="weui-cell weui-cell_access kt-exit">
<p class="weui-cell__bd">
<p style="color:red;">退出登录</p>
</p>
</a>
</p>
</section>
</p>
</p>
<script type="text/javascript">
require(['jquery','weui'],function($){
});
</script>
</body>
</html>Error message: 
![[Web front-end] Node.js quick start](https://img.php.cn/upload/course/000/000/067/662b5d34ba7c0227.png)
Manually declare dependencies
And do not defer and async when loading require.js in 999.html