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Pragma header

files/en-us/web/http/reference/headers/pragma/index.md

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{{Deprecated_Header}}

The HTTP Pragma header is an implementation-specific header that may have various effects along the request-response chain. This header serves for backwards compatibility with HTTP/1.0 caches that do not support the {{HTTPHeader("Cache-Control")}} HTTP/1.1 header.

[!NOTE] The Pragma header is not specified for HTTP responses and is therefore not a reliable replacement for the HTTP/1.1 Cache-Control header, although its behavior is the same as Cache-Control: no-cache if the Cache-Control header field is omitted in a request. Use Pragma only for backwards compatibility with HTTP/1.0 clients.

<table class="properties"> <tbody> <tr> <th scope="row">Header type</th> <td> {{Glossary("Request header")}}, {{Glossary("Response header")}} (response behavior is not specified and is implementation-specific). </td> </tr> <tr> <th scope="row">{{Glossary("Forbidden request header")}}</th> <td>No</td> </tr> <tr> <th scope="row"> {{Glossary("CORS-safelisted response header")}} </th> <td>Yes</td> </tr> </tbody> </table>

Syntax

http
Pragma: no-cache

Directives

  • no-cache
    • : Same as Cache-Control: no-cache. Forces caches to submit the request to the origin server for validation before a cached copy is released.

Examples

http
Pragma: no-cache

Specifications

{{Specifications}}

Browser compatibility

{{Compat}}

See also

  • {{HTTPHeader("Cache-Control")}}
  • {{HTTPHeader("Expires")}}