老师，我的这个错误怎么解决啊

# 具体遇到的问题

# 报错信息的截图

# 相关课程内容截图

# 尝试过的解决思路和结果

# 粘贴全部相关代码，切记添加代码注释（请勿截图）

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>用户注册</title>
<link rel="stylesheet" type="text/css" href="css/style.css">
</head>
<body>
<div class="register">
<p class="title">
<span>登录</span>
<span class="current">注册</span>
</p>
<div class="form">
<div>
<span>+86</span>
<input type="text" name="user" id="user" placeholder="请输入注册手机号" autocomplete="off" />
<i id="user_icon"></i>
<p class="info" id="user_info"></p>
</div>
<div>
<input type="password" name="password" id="pwd" placeholder="请设置密码">
<i></i>
<p class="info"></p>
</div>
<p class="button">
<a href="javascript:void(0)" id="sigup-btn" class="btn">注册</a>
</p>
</div>
</div>
<script type="text/javascript" src="js/ajax.js"></script>
<script type="text/javascript">
var user=document.getElementById("user"),
pwd=document.getElementById("pwd"),
sigup=document.getElementById("sigup-btn"),
user_info=document.getElementById("user_info"),
user_icon=document.getElementById("user_icon");
// 检查用户
function checkUser(){
var userVal=user.value,
userReg = /^1[3578]\d{9}$/;
// 验证手机号是否有效
if (!userReg.test(userVal)) {
user_info.innerHTML="手机号码无效";
user_icon.className='no';
}else{
user_info.innerHTML="";
user_icon.className='ok';
// 发起请求
$.ajax({
url:"http://localhost/jSon和Ajax登录功能/register/server/isUserRepeat.php",
method:"post",
asaync:true,
data:{username:userVal},
success:function(data){
console.log(data);
}
})
}
}

// 绑定事件，检测用户是否注册过
user.addEventListener("blur",checkUser,false);
</script>
</body>
</html>

*{
margin:0;
padding:0;
}

body{
background:#333;
}

.register{
width:300px;
height:270px;
margin:80px auto;
padding:15px 30px;
background:#eee;
border-radius:5px;
}

.title{
height:35px;
}
.title span{
font-size:16px;
font-weight:bold;
color:#666;
margin-right:30px;
cursor:pointer;
display:inline-block;
padding-top:5px;
}
.title span.current{
color:#f00;
}

.form div{
width:290px;
height:30px;
border-radius:8px;
background:#fff;
margin-bottom:25px;
padding:8px 10px;
position:relative;
}
.form div span{
display:inline-block;
padding-top:6px;
padding-right:3px;
color:#666;
}
.form div input{
border:none;
outline:none;/*外边框*/
font-size:16px;
color:#666;
background:none
}

.form div i{
position:absolute;
width:16px;
height:16px;
right:12px;
top:14px;
}

.form div i.ok{
background:url(../img/icon.png) no-repeat 0 -67px;
}
.form div i.no{
background:url(../img/icon.png) no-repeat -17px -67px;
}

.form .info{
margin-top:14px;
color:red;
padding-left:2px;
}

.button{
padding-top:7px;

}
.button a{
display:block;
width:100%;
height:45px;
line-height:45px;
text-align:center;
text-decoration:none;
background:#f20d0d;
color:#fff;
border-radius:30px;
font-size:16px;
}

var $={
ajax:function(options){
var xhr=null,// XMLHttpRequestRequest对象
url=options.url,//url地址
method=options.method || "get",//传输方式，默认为get
asaync=typeof options.asaync === "undefined"?true:options.asaync,
data=options.data || null,
params="", //参数
callback=options.success, //ajax请求成功的函数
error=options.error;//请求失败
// 将data的对象字面量的形式转换为字符串形式
if (data) {
for(var i in data){
params+=i+"="+data[i]+"&";
}
params=params.replace(/&$/,"");
}
// 根据method的值改变url
if (method === "get") {
url+="?"+params;
}
if (typeof XMLHttpRequest != "undefined") {
xhr=new XMLHttpRequest();
}
else if (typeof ActiveXObject != "undefined") {
//将所有可能出现的ActiveXObject放在一个数组中
var xhrArr=['Microsoft.XMLHTTP','MSXML2.XMLHTTP.6.0','MSXML2.XMLHTTP.5.0','MSXML2.XMLHTTP.4.0','MSXML2.XMLHTTP.3.0','MSXML2.XMLHTTP.2.0']
var len=xhrArr.length;
for(var i=0;i<len;i++){
try{
// 创建XMLHttpRequest对象
xhr=new ActiveXObject(xhrArr[i]);
break;
}
catch(e){

}
}
}else{
throw Error("其他的问题");
}
xhr.onreadystatechange = function(){
if (xhr.readyState ===4) {
if ((xhr.status>=200&&xhr.status<300)||xhr.status===304) {
callback && callback(JSON.parse(xhr.responseText));
}else{
error && error();
}
}
}
// 创建请求
xhr.open(method,url,asaync);
// post请求需要设置头部信息
xhr.setRequestHeader("Content-type","application/x-www-form-urlencoded");
// 发送请求
xhr.send(params);
},

// 跨域
jsonp:function(){

}
}