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webRequest.StreamFilter.onerror

An event handler that will be called when an error occurs. This is most often because an invalid request ID was passed into webRequest.filterResponseData().

After this event is fired, the webRequest.StreamFilter.error property will contain a message giving more information about the error.

Note that this event is not triggered for network errors.

Browser compatibility

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	WebView Android	Chrome Android	Firefox for Android	Opera Android	Safari on IOS	Samsung Internet
`onerror`	No	No	57	?	No	No	?	?	57	?	No	?

Examples

This example adds an onerror listener which logs the value of webRequest.StreamFilter.error.

function listener(details) {
  // This example seems not useful because,
  // an extension would use "details.requestId"
  let filter = browser.webRequest.filterResponseData("12345");

  filter.onerror = (event) => {
    console.log(`Error: ${filter.error}`);
  }
}

browser.webRequest.onBeforeRequest.addListener(
  listener,
  {urls: ["<all_urls>"], types: ["main_frame"]},
  ["blocking"]
);

This example uses no "blocking".

function listener(details) {
  let filter = browser.webRequest.filterResponseData(details.requestId);

  filter.onerror = (event) => {
    console.log(`Error: ${filter.error}`); // Error: Invalid request ID
  }
}

browser.webRequest.onBeforeRequest.addListener(
  listener,
  {urls: ["<all_urls>"], types: ["main_frame"]}
);

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https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/API/webRequest/StreamFilter/onerror