Running html on a local host gives strange error message

Question

I am trying to get my index.html file to run using the live server extension on vs code. I got this very strange error "ReferenceError: hlIcons is not defined", but I don't ever use the phrase 'h1Icons' in my code. I tried to look up what h1Icons was and I found nothing. I then made an empty project and opened it with live server and got the same error. I also tried to open it using http-server and still got the same error.

Picture of error on browser console

EDIT: this error only shows up on chrome

Answer 1

TL;DR

This error likely appears due to an error occurring from a Chrome extension. Even though it won't affect your development process, you can disable your extensions, and the error should disappear.

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Common Errors

Sometimes, extensions can cause some errors. For example, there are a few extensions in the Chrome Web Store which cause this error:

Unchecked runtime.lastError: The message port closed before a response was received.

^{P.S. This error also always comes for me, due to my Norton extension.}

However, you can safely ignore these types of errors.

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Your Error

In your case, you are getting this error:

Uncaught ReferenceError: h1Icons is not defined
    at exam_tools.js:235:22513
    at exam_tools.js:235:22513

This is most likely due to an extension trying to run a JavaScript file, but running into an error. In these cases, it would output in the console.

These are the reasons an extension could be causing this.

• You are only getting this error in Chrome. Chances are you don't have this extension in Edge, for example.
• The file the error is coming from is called exam_tools.js, which you don't have in your project (proved when you started a fresh project).
• The line number and column number are very large (:235:22513), because the file is most likely minified.

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The Solution

You don't have to worry about this error, as it won't affect your development process.

However, if you find the error message annoying, then you can try and disable all of your extensions, which should solve the issue, as then the extension which is outputting the error can't do so anymore.