Focus the Delete Button in a Confirm Dialog

instance.addEventListener("annotations.willChange", (event) => {
  const annotation = event.annotations.get(0);
  if (
    event.reason === PSPDFKit.AnnotationsWillChangeReason.DELETE_START
  ) {
    console.log("Will open deletion confirmation dialog");
    // We need to wrap the logic in a `setTimeOut()`, because the modal will be rendered on the next tick.
    setTimeout(function () {
      // The button is in the context of the PSPDFKit iframe.
      const button = instance.contentDocument.getElementsByClassName(
        "PSPDFKit-Confirm-Dialog-Button-Confirm"
      )[0];
      button.focus();
    }, 0);
  }
});