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• 句法
• 范例
• 规范
• 浏览器兼容性
• 另请参阅
• 相关话题

mode 只读特性在 Request interface contains the mode of the request (e.g., cors , no-cors , same-origin ，或 navigate .) This is used to determine if cross-origin requests lead to valid responses, and which properties of the response are readable.

句法

var myMode = request.mode;
					

值

A RequestMode 值。

The associated mode , available values of which are:

• same-origin — If a request is made to another origin with this mode set, the result is simply an error. You could use this to ensure that a request is always being made to your origin.
• no-cors — Prevents the method from being anything other than HEAD , GET or POST , and the headers from being anything other than simple headers . If any ServiceWorkers intercept these requests, they may not add or override any headers except for those that are simple headers . In addition, JavaScript may not access any properties of the resulting 响应 . This ensures that ServiceWorkers do not affect the semantics of the Web and prevents security and privacy issues arising from leaking data across domains.
• cors — Allows cross-origin requests, for example to access various APIs offered by 3rd party vendors. These are expected to adhere to the CORS protocol . Only a limited set of headers are exposed in the 响应 , but the body is readable.
• navigate — A mode for supporting navigation. The navigate value is intended to be used only by HTML navigation. A navigate request is created only while navigating between documents.

Default mode

Requests can be initiated in a variety of ways, and the mode for a request depends on the particular means by which it was initiated.

例如，当 Request object is created using the Request.Request constructor, the value of the mode property for that Request 被设为 cors .

However, for requests created other than by the Request.Request constructor, no-cors is typically used as the mode; for example, for embedded resources where the request is initiated from markup, unless the crossorigin attribute is present, the request is in most cases made using the no-cors mode — that is, for the <link> or <script> elements (except when used with modules), or <img> , <audio> , <video> , <object> , <embed> ，或 <iframe> 元素。

范例

In the following snippet, we create a new request using the Request.Request() constructor (for an image file in the same directory as the script), then save the request mode in a variable:

var myRequest = new Request('flowers.jpg');
var myMode = myRequest.mode; // returns "cors" by default
					

规范

规范	状态	注释
Fetch The definition of 'mode' in that specification.	实时标准	初始定义

浏览器兼容性

The compatibility table on 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. 更新 GitHub 上的兼容性数据

	桌面						移动
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
mode	Chrome 42	Edge 14	Firefox 39	IE No	Opera 29	Safari No	WebView Android 49	Chrome Android 49	Firefox Android No	Opera Android No	Safari iOS No	Samsung Internet Android 5.0
navigate mode	Chrome 49	Edge ≤18	Firefox 46	IE No	Opera ?	Safari No	WebView Android No	Chrome Android 49	Firefox Android No	Opera Android No	Safari iOS No	Samsung Internet Android 5.0

图例

完整支持

完整支持

不支持

不支持

兼容性未知 ?

兼容性未知

实验。期望将来行为有所改变。

实验。期望将来行为有所改变。

另请参阅

• ServiceWorker API
• HTTP access control (CORS)
• HTTP

元数据

• 最后修改： Mar 18, 2019

相关话题

1. Request
2. 构造函数

   1. Request()
3. 特性

   1. body
   2. bodyUsed
   3. cache
   4. context
   5. credentials
   6. destination
   7. headers
   8. integrity
   9. method
   10. mode
   11. redirect
   12. referrer
   13. referrerPolicy
   14. url
4. 方法

   1. arrayBuffer()
   2. blob()
   3. clone()
   4. formData()
   5. json()
   6. text()