Does fetch not work in the index.html file?

I'm trying to get my json files from my assets folder into the resource variable automatically instead of inputting them manually, but I keep getting error messages like:
TypeError: Failed to fetch
My code:

var resources = {
  "images": [{"file":"icon.png","version":0,"size":0,"properties":{}}],
  "assets": [],
  "maps": {},
  "sounds": [],
  "music": []
};
fetch('assets/')
.then(response => response.text())
.then(data => {
    const parser = new DOMParser();
    const doc = parser.parseFromString(data, 'text/html');
    const fileList = Array.from(doc.querySelectorAll('a'))
        .map(a => a.textContent)
        .filter(name => name.endsWith('.json'))
    resources.assets = fileList;
});

Ctrl - Alt - I - see what error message you have.

Why don't you load assets in the program using asset_manager ?

Because doesn't that load stuff from the resources variable I want to have it automatically scan the static/assets folder and add those to the resource variable. I am using the asset_manager inside the regular code btw.

Access to fetch at 'file:///C:/' from origin 'null' has been blocked by CORS policy: Cross origin requests are only supported for protocol schemes: http, data, isolated-app, chrome-extension, chrome, https, chrome-untrusted.

index.html:1 Access to internal resource at 'file:///C:/Users/......./manifest.json' from origin 'null' has been blocked by CORS policy: Cross origin requests are only supported for protocol schemes: http, data, isolated-app, chrome-extension, chrome, https, chrome-untrusted.

https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS/Errors/CORSRequestNotHttp?utm_source=devtools&utm_medium=firefox-cors-errors&utm_campaign=default

I have such errors (Chrome and Firefox)

Both indicate that the browser has blocked the request to the resources.

You can

• modify the flags in the browser settings. But this will work on all websites and is dangerous.

• set up a local server that will share this folder and you will run index.html as localhost/index.html

• build an application for windows / mac (export your application to .exe) and see if Elektron allows you to download data locally.

I once tried to force the browser to run *.txt files (which contained javascript code) as a .js file but I also received a security policy error and it didn't work.

https://juplo.de/bypassing-the-same-origin-policiy-for-loal-files-during-development/

https://developer.mozilla.org/en-US/docs/Web/Security/Same-origin_policy