Calling setCookie in Ajax fails, but IDE has no errors

I have been working on a project recently, and it has been delayed for a long time because of this small mistake. I hereby record it.

Front-end code:

Simplify the code in the form to

<form id="login-form" method="post">
    <input type="text" placeholder="请输入您的用户名" class="form-control required" name="username" id="username" tips="请填写用户名" />
    <input type="password" placeholder="请输入密码" class="form-control required" id="password" name="password" tips="请填写密码" />
    <input type="text" name="cpacha" id="cpacha" maxlength="4" class="form-control required" placeholder="验证码" tips="请填验证码" >
</form>

Want to use ajax to determine whether the user name exists to set a cookie, the js code is as follows

<script src="admin/js/jquery.min.js"></script>
<!-- Include all compiled plugins (below), or include individual files as needed -->
<script src="admin/js/bootstrap.min.js"></script>
<script src="admin/js/util.js"></script>
<script type="application/javascript"></script>
<script type="text/javascript">
  $(document).ready(function(){
    $("#submit-btn").click(function(){
      if(!checkForm("login-form")){
        return;
      }
      var user={};
      user.username= $("#username").val();
      user.password =$("#password").val();
      user.cpacha = $("#cpacha").val();

      $.ajax({
        url:'/system/login',
        type:'POST',
        //data:{username:username,password:password,cpacha:cpacha},
        data:user,
        dataType:'json',
        success:function(data){
          if(data.code == 0){
            alert("setCookie前");
            setCookie("user",data.content,1);
            alert("setCookie后");
            window.location.href = 'index';

          }else{
            showErrorMsg(data.msg);
          }
        },
        error:function(data){
          alert('网络错误!');
        }
      });
    });
  });

</script>

The setCookie() method in util.js cannot set the value of the cookie when it is executable , and the login page cannot be jumped, but the background can be successfully matched.

The result is as follows:

IDE without any errors

 But when I open the browser and press F12 to enter the console , I found some clues

The js files of the  login page are all popular, and there is a line in it, which aroused my vigilance.

Uncaught ReferenceError: setCookie is not defined

setCookie is not defined,

So press Ctrl and click the mouse, and find that you can enter util.js

function setCookie(name, value, days) {
    var d = new Date;
    d.setTime(d.getTime() + 24*60*60*1000*days);
    window.document.cookie = name + "=" + value + ";path=/;expires=" + d.toGMTString();
    //console.log(name + "=" + value + ";path=/;expires=" + d.toGMTString())
    var strCookie=window.document.cookie;
     alert("function setCookie里"+strCookie);
}

The setCookie method is also defined. When I was at a loss, I suddenly remembered whether javaScript has an execution order in the page, so I put

<script>XXX</script>

put in the front

But still the problem.

When I was about to collapse, an epiphany came to me, and I thought about it carefully, is there a path reference error ?

 View folder hierarchy

 Add "/" to src in <script></script>

which is:

<script src="/admin/js/jquery.min.js"></script>
<!-- Include all compiled plugins (below), or include individual files as needed -->
<script src="/admin/js/bootstrap.min.js"></script>
<script src="/admin/js/util.js"></script>
<script type="application/javascript"></script>

 Works perfectly! ! ! !