Accept
The Accept
request HTTP header indicates which content types, expressed as MIME types, the client is able to understand. The server uses content negotiation to select one of the proposals and informs the client of the choice with the Content-Type
response header. Browsers set required values for this header based on the context of the request. For example, a browser uses different values in a request when fetching a CSS stylesheet, image, video, or a script.
Header type | Request header |
---|---|
Forbidden header name | no |
CORS-safelisted request header |
yes, with the additional restriction that values can't contain a
CORS-unsafe request header byte: 0x00-0x1F (except 0x09 (HT)),
"():<>?@[\]{} , and 0x7F (DEL).
|
Syntax
http
Accept: <MIME_type>/<MIME_subtype>
Accept: <MIME_type>/*
Accept: */*
// Multiple types, weighted with the quality value syntax:
Accept: text/html, application/xhtml+xml, application/xml;q=0.9, image/webp, */*;q=0.8
Directives
<MIME_type>/<MIME_subtype>
-
A single, precise MIME type, like
text/html
. <MIME_type>/*
-
A MIME type, but without a subtype.
image/*
corresponds toimage/png
,image/svg
,image/gif
, and other image types. */*
-
Any MIME type
;q=
(q-factor weighting)-
A value used is placed in an order of preference expressed using a relative quality value called the weight.
Examples
http
Accept: text/html
Accept: image/*
// General default
Accept: */*
// Default for navigation requests
Accept: text/html, application/xhtml+xml, application/xml;q=0.9, */*;q=0.8
Specifications
Specification |
---|
HTTP Semantics # field.accept |
Browser compatibility
BCD tables only load in the browser
See also
- HTTP content negotiation
- List of default Accept values
- A header with the result of the content negotiation:
Content-Type
- Other similar headers:
TE
,Accept-Encoding
,Accept-Language