Service-Worker-Navigation-Preload request header indicates that the request was the result of a
fetch() operation made during service worker navigation preloading.
It allows a server to respond with a different resource than for a normal
If a different response may result from setting this header, the server must set
Vary: Service-Worker-Navigation-Preload to ensure that the different responses are cached.
An arbitrary value that indicates what data should be sent in the response to the preload request. This defaults to
true. It maybe set to any other string value in the service worker, using
The header below is sent by default.
The service worker can set a different header value using
For example, in order to request that a fragment of the requested resource be returned in JSON format, the value could be set with the string
|Service Workers 1 |
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