Device-Memory - HTTP 编辑

Secure context

This feature is available only in secure contexts (HTTPS), in some or all supporting browsers.

Experimental

This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

The Device-Memory header is a Device Memory API header that works like Client Hints header which represents the approximate amount of RAM client device has.

Note: Client Hints are accessible only on secure origins (via TLS). Server has to opt in to receive Device-Memory header from the client by sending Accept-CH and Accept-CH-Lifetime response headers.

Syntax

The amount of device RAM can be used as a fingerprinting variable, so values for the header are intentionally coarse to reduce the potential for its misuse. The header takes on the following values: 0.25, 0.5, 1, 2, 4, 8.

Device-Memory: <number>

Examples

Server first needs to opt in to receive Device-Memory header by sending the response headers Accept-CH containing Device-Memory and Accept-CH-Lifetime.

Accept-CH: Device-Memory
Accept-CH-Lifetime: 86400

Then on subsequent requests the client might send Device-Memory header back:

Device-Memory: 1

Specifications

Browser compatibility

BCD tables only load in the browser

See also

• Device Memory API
• Accept-CH
• Accept-CH-Lifetime
• Vary
• Navigator.deviceMemory