问题
I thought same origin implies no CORS, and vice-versa. What's the difference between the two options for JavaScript's Fetch API's mode option?
Also, in the specs, it says:
Even though the default request mode is "no-cors", standards are highly discouraged from using it for new features. It is rather unsafe.
Why is it unsafe? Source: https://fetch.spec.whatwg.org/#requests
回答1:
With same-origin you can perform requests only to your origin, otherwise the request will result in an error.
With no-cors, you can perform requests to other origins, even if they don't set the required CORS headers, but you'll get an opaque response.
You can read more on MDN: https://developer.mozilla.org/en-US/docs/Web/API/Request/mode and https://developer.mozilla.org/en-US/docs/Web/API/Response/type.
来源：https://stackoverflow.com/questions/35910790/whats-the-difference-between-same-origin-and-no-cors-for-javascripts-fetch