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Add-ons

webRequest.ResourceType

This type is a string, which represents the context in which a resource was fetched in a web request.

It's used to filter the requests you listen to using the webRequest API. For example: you can listen to requests only for images, or only for scripts.

Type

Values of this type are strings. Possible values are:

beacon
Requests sent through the Beacon API.
csp_report
Requests sent to the report-uri given in the Content-Security-Policy header, when an attempt to violate the policy is detected.
font
Web fonts loaded for a @font-face CSS rule.
image
Resources loaded to be rendered as image, except for imageset on browsers that support that type (see browser compatibility below).
imageset
Images loaded by a <picture> element or given in an <img> element's srcset attribute.
main_frame
Top-level documents loaded into a tab.
media
Resources loaded by a  <video> or  <audio> element.
object
Resources loaded by an <object> or <embed> element.
Browsers that don't have a dedicated object_subrequest type (see browser compatibility below), also label subsequent requests sent by the plugin as object.
object_subrequest
Requests sent by plugins.
ping
Requests sent to the URL given in a hyperlink's ping attribute, when the hypelink is followed.
Browsers that don't have a dedicated beacon type (see browser compatibility below), also label requests sent through the Beacon API as ping.
script
Code that is loaded to be executed by a <script> element or running in a Worker.
stylesheet
CSS stylesheets loaded to describe the representation of a document.
sub_frame
Documents loaded into an <iframe> or <frame> element.
web_manifest
Web App Manifests loaded for websites that can be installed to the homescreen.
websocket
Requests initiating a connection to a server through the WebSocket API.
xbl
XBL bindings loaded to extend the behavior of elements in a document.
xml_dtd
DTDs loaded for an XML document.
xmlhttprequest
Requests sent by an XMLHttpRequest object or through the Fetch API.
xslt
XSLT stylesheets loaded for transforming an XML document.
other
Resources that aren't covered by any other available type.

Browser compatibility

ChromeEdgeFirefoxFirefox for AndroidOpera
Basic Support44 No454831
ping491 No4548361
font49 No454836
media58 No454845
websocket58 No454845
csp_report58 No454845
xbl No No4548 No
xslt No No4548 No
beacon No No4548 No
xml_dtd No No4548 No
imageset No No4548 No
web_manifest No No4548 No
object_subrequest No No552552 No

1. Requests sent by navigator.sendBeacon(), and CSP reports in Chrome 49-57 (Opera 36-44), are also labeled as `ping`.

2. Requests have been reported as `object_subrequest` before, but the type was missing in the `ResourceType` object before Firefox 55.

Acknowledgements

This API is based on Chromium's chrome.webRequest API. This documentation is derived from web_request.json in the Chromium code.

Microsoft Edge compatibility data is supplied by Microsoft Corporation and is included here under the Creative Commons Attribution 3.0 United States License.

Document Tags and Contributors

 Contributors to this page: wbamberg, snoack, Wladimir_Palant, rolfedh
 Last updated by: wbamberg,