Secure context
This feature is available only in secure contexts (HTTPS), in some or all supporting browsers.
这是一个实验中的功能
此功能某些浏览器尚在开发中，请参考浏览器兼容性表格以得到在不同浏览器中适合使用的前缀。由于该功能对应的标准文档可能被重新修订，所以在未来版本的浏览器中该功能的语法和行为可能随之改变。
DPR请求头是“ 客户端提示”消息头，它代表客户端设备的像素比(DPR)，该比例是与每个CSS像素相对应的物理设备像素的数量。
| Header type | Request header |
|---|---|
| Forbidden header name | ? |
Note: Client Hints are accessible only on secure origins (via TLS). Server has to opt in to receive DPR header from the client by sending Accept-CH and Accept-CH-Lifetime response headers.
语法
DPR: <number>
示例
Server first needs to opt in to receive DPR header by sending the response headers Accept-CH containing DPR and Accept-CH-Lifetime.
Accept-CH: DPR Accept-CH-Lifetime: 86400
Then on subsequent requests the client might send DPR header back:
DPR: 1.0
浏览器兼容
The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.
| Desktop | Mobile | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
DPR | Chrome Full support 46 | Edge Full support ≤79 | Firefox ? | IE ? | Opera Full support 33 | Safari ? | WebView Android Full support 46 | Chrome Android Full support 46 | Firefox Android ? | Opera Android Full support 33 | Safari iOS ? | Samsung Internet Android Full support 5.0 |
Legend
- Full support
- Full support
- Compatibility unknown
- Compatibility unknown
- Experimental. Expect behavior to change in the future.
- Experimental. Expect behavior to change in the future.