webRequest.StreamFilter.write()

Writes some response data to the output stream.

You can only call this function after the onstart event has fired.

Syntax

js
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

Examples

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

js
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.replaceAll("Example", "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"],
);