Why doesn't JS work in visual code?

Question

JavaScript

Hello. There is a working code, but in VS Code + open live server it doesn't work. More precisely, javascript does not work at all

var login = document.querySelector(".login-link");
    var loginpopup = document.querySelector(".modal-login");
    
    login.addEventListener("click", function (event) {
        event.preventDefault();
        loginpopup.classList.add("modal-show");
    });

UPD. It works in codepen, but on LAN, through browser synchronization with VS code, it throws a link. Faced with this? Maybe something needs to be included in VS code?
UPD 2.0. I installed a debugger in VS code and it gave this.

var login = document.querySelector('.login-link');
^
ReferenceError: document is not defined
at Object. (h:\barbershop\modal.js:1:13)
at Module._compile (internal/modules/cjs/loader.js:776:30)
at Object.Module._extensions..js (internal/modules/cjs/loader .js:787:10)
at Module.load (internal/modules/cjs/loader.js:653:32)
at tryModuleLoad (internal/modules/cjs/loader.js:593:12)
at Function.Module._load ( internal/modules/cjs/loader.js:585:3)
at Function.Module.runMain (internal/modules/cjs/loader.js:829:12)
at startup (internal/bootstrap/node.js:283:19)
at bootstrapNodeJSCore (internal/bootstrap/node.js:622:3)

But, again, the code is working. You can look here for a working version - https://codepen.io/ruslan-lysenko/pen/rEgqBe
Soon I'll be crazy and switch to notepad++

Answer 1

Good day!
It doesn't appear that your html page is linking to a js file: Apparently codepen does this automatically.

Answer 2

Turn off what is doing the file synchronization and updating, and then try to do what you are trying.