Informs the server about the human language the server is expected to send back. This is a hint and is not
necessarily under the full control of the user: the server should always pay attention not to override an
explicit user choice (like selecting a language from a dropdown).
Indicates if the resource transmitted should be displayed inline (default behavior without the header), or if it
should be handled like a download and the browser should present a “Save As” dialog.
Allows web developers to experiment with policies by monitoring, but not enforcing, their effects. These
violation reports consist of JSON documents sent via an HTTP POST request to the specified URI.
A unique string identifying the version of the resource. Conditional requests using If-Match and If-None-Match
use this value to change the behavior of the request.
Allows sites to opt in to reporting and/or enforcement of Certificate Transparency requirements, which prevents
the use of misissued certificates for that site from going unnoticed. When a site enables the Expect-CT header,
they are requesting that Chrome check that any certificate for that site appears in public CT logs.
Makes the request conditional, and expects the entity to be transmitted only if it has been modified after the
given date. This is used to transmit data only when the cache is out of date.
Makes the request conditional, and applies the method only if the stored resource doesn't match any of the given
ETags. This is used to update caches (for safe requests), or to prevent to upload a new resource when one already
exists.
Creates a conditional range request that is only fulfilled if the given etag or date matches the remote resource.
Used to prevent downloading two ranges from incompatible version of the resource.
Makes the request conditional, and expects the entity to be transmitted only if it has not been modified after
the given date. This ensures the coherence of a new fragment of a specific range with previous ones, or to
implement an optimistic concurrency control system when modifying existing documents.
The last modification date of the resource, used to compare several versions of the same resource. It is less
accurate than ETag, but easier to calculate in some environments. Conditional requests using If-Modified-Since
and If-Unmodified-Since use this value to change the behavior of the request.
Implementation-specific header that may have various effects anywhere along the request-response chain.
Used for backwards compatibility with HTTP/1.0 caches where the Cache-Control header is not yet present.
It is a request header that indicates the request's destination to a server. It is a Structured Header whose
value is a token with possible values audio, audioworklet, document, embed, empty, font, image, manifest, object,
paintworklet, report, script, serviceworker, sharedworker, style, track, video, worker, xslt, and
nested-document.
It is a request header that indicates the request's mode to a server. It is a Structured Header whose value is a
token with possible values cors, navigate, nested-navigate, no-cors, same-origin, and websocket.
It is a request header that indicates the relationship between a request initiator's origin and its target's
origin. It is a Structured Header whose value is a token with possible values cross-site, same-origin, same-site,
and none.
It is a request header that indicates whether or not a navigation request was triggered by user activation. It is
a Structured Header whose value is a boolean so possible values are ?0 for false and ?1 for true.
Specifies origins that are allowed to see values of attributes retrieved via features of the Resource Timing API,
which would otherwise be reported as zero due to cross-origin restrictions.
Sends a signal to the server expressing the client’s preference for an encrypted and authenticated response, and
that it can successfully handle the upgrade-insecure-requests directive.
Contains a characteristic string that allows the network protocol peers to identify the application type,
operating system, software vendor or software version of the requesting software user agent.
Controls DNS prefetching, a feature by which browsers proactively perform domain name resolution on both links
that the user may choose to follow as well as URLs for items referenced by the document, including images, CSS,
JavaScript, and so forth.
