v147 · proposed IWA API · member reference

WebPrintJob.cancel()

Requests immediate cancellation of a submitted job. It is deliberately best effort: a job may already have finished.

Proposal and implementation differ from the old overviewChromeStatus currently records this API as Proposed, not shipped. This reference follows the current WICG IDL and Chromium source; test in the intended IWA configuration and feature-detect rather than relying on the v147 label.

Syntax

job.cancel();
// undefined

Inputs

No parameters. You may alternatively put an AbortSignal in submit attributes before creating the job.

Outputs

Returns undefined; it is not a promise and does not report cancellation success.

Errors

No cancellation-specific exception/rejection contract is specified. Application code must observe subsequent state rather than treating the return as confirmation.

Context and permission

The IDL requires a secure, isolated context. The specification also defines the web-printing Permissions Policy with default allowlist self; Chromium additionally checks an isolated context and cross-origin isolation before getPrinters(). The current proposal requires express, origin-specific consent triggered by enumeration. The exact chooser scope, persistence, and whether a later operation prompts again remain user-agent UX, not a settled web contract.

Lifecycle, cancellation, and cleanup

Chromium ignores repeated cancellation and calls after terminal state; it clears the abort algorithm when it makes its request. A signalled AbortSignal invokes the same method. The spec says cancellation aborts immediately, but its example warns it might take no effect after completion.

Examples

function requestCancel(job) {
  const state = job.attributes().jobState;
  if (!["completed", "canceled", "aborted"].includes(state)) {
    job.cancel();
  }
}

Browser compatibility

Current public compatibility evidence (checked 2026-07-26)
Runtime	Status	Evidence
Chrome (general)	Proposed and not released. ChromeStatus lists I2S desktop target 147, which is not release proof. Do not infer general desktop Chrome support.	ChromeStatus
Current Chromium service	Implemented only when built with `IS_CHROMEOS && USE_CUPS`; otherwise `getPrinters()` has no service and throws `SecurityError`.	Chromium manager implementation
Android / mobile	ChromeStatus Android is `null`; no public mobile release exists. The current ChromeOS+CUPS-only service path does not expose the service on Android.	ChromeStatus; implementation guard
Firefox	No signal; no BCD member record found.	ChromeStatus position; BCD API data
Safari	No signal; no BCD member record found.	ChromeStatus position; BCD API data
webstatus.dev	No feature entry found for this query; this is not proof of absence from browsers.	webstatus query

Security and privacy

Printer names, IDs, capabilities and state can fingerprint a device and reveal printing activity. A compromised IWA could create unwanted jobs or denial of service. Minimize enumeration and polling, do not expose attributes to untrusted content, validate documents before submitting, and offer an app-level confirmation/audit trail. The spec requires isolation and consent; it does not make printer information non-sensitive.