Getting Error in execution of web app

I have created a flutter demo web app and then created the release build using this command.

flutter build web

but when i am opening the index.html file from build–>web folder, as a file protocol in browser without any local server, it is throwing error.

Access to XMLHttpRequest at ‘file:///home/rajnish/Downloads/flutterDemo/build/web/assets/FontManifest.json’ from origin ‘null’ has been blocked by CORS policy: Cross origin requests are only supported for protocol schemes: http, data, chrome, chrome-extension, https.

Uncaught Failed to load asset at “assets/FontManifest.json” (0)
Uncaught (in promise) TypeError: Failed to register a ServiceWorker: The URL protocol of the current origin (‘null’) is not supported. at index.html:24

My requirement is to run the web application using file protocol.