[Vuejs]-Update not working using vuejs3 and json it gives empty for the course fields

So there are a few issues with your code sample.

First, there is a typo: hearders should be headers

and second, your button element should have the type="submit". The reason for this is you are using the form element. To trigger the form’s associated @submit handler, a button within form must have the correct submit type.

You can read more about it here: https://developer.mozilla.org/en-US/docs/Web/HTML/Element/form