该特性已经从 Web 标准中删除,虽然一些浏览器目前仍然支持它,但也许会在未来的某个时间停止支持,请尽量不要使用该特性。

The deprecated 弃用context所述的只读属性请求接口包含请求的上下文(例如,audioimageiframe)。这定义了要获取的资源类型。它已由Request.destination”,“ destination属性取代。 This defines what sort of resource is being fetched. This has been replaced by the destination property.

The context of a request is only relevant in the 请求的上下文仅与ServiceWorker API相关服务人员可以根据URL是用于图像还是可嵌入对象(例如<视频>iframe等)进行决策。; a service worker can make decisions based on whether the URL is for an image, or an embeddable object such as a <video>, iframe, etc.

Note注意:您可以在“ 获取规范请求上下文”部分中找到不同可用上下文的完整列表,包括关联的上下文框架类型,CSP指令和平台功能示例 section.


var myContext = request.context;


A RequestContext value.一个RequestContext值。


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 context in a variable:在以下代码段中,我们使用Request.Request()}构造函数创建一个新请求(用于与脚本位于同一目录中的图像文件),然后将请求上下文保存在变量中:

var myRequest = new Request('flowers.jpg');
var myContext = myRequest.context; // returns the empty string by default

Browser compatibility浏览器兼容性

BCD tables only load in the browser