webRequest.StreamFilter.write()

Writes some response data to the output stream.
 
You can only call this function after the onstart event has fired.
 

Syntax

filter.write(
  data    // ArrayBuffer or Uint8Array
)

Parameters

data
Uint8Array or ArrayBuffer: array of bytes containing the data to pass to the browser's rendering engine.

Return value

None.

Browser compatibility

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxOperaFirefox for Android
Basic supportChrome No support NoEdge No support NoFirefox Full support 57Opera No support NoFirefox Android Full support 57

Legend

Full support  
Full support
No support  
No support

Examples

This example uses write() to replace "Example" in the response with "WebExtension Example".

function listener(details) {
  let filter = browser.webRequest.filterResponseData(details.requestId);
  let decoder = new TextDecoder("utf-8");
  let encoder = new TextEncoder();

  filter.ondata = event => {
    let str = decoder.decode(event.data, {stream: true});
    // Just change any instance of Example in the HTTP response
    // to WebExtension Example.
    str = str.replace(/Example/g, 'WebExtension Example');
    filter.write(encoder.encode(str));
    filter.disconnect();
  }

  //return {}; // not needed
}

browser.webRequest.onBeforeRequest.addListener(
  listener,
  {urls: ["https://example.com/*"], types: ["main_frame"]},
  ["blocking"]
);

Document Tags and Contributors

Contributors to this page: kernp, wbamberg
Last updated by: kernp,