gecko-dev/dom/html/test/browser_submission_flush.js

"use strict";
// Form submissions triggered by the Javascript 'submit' event listener are
// deferred until the event listener finishes. However, changes to specific
// attributes ("action" and "target" attributes) need to cause an immediate
// flush of any pending submission to prevent the form submission from using the
// wrong action or target. This test ensures that such flushes happen properly.

const kTestPage =
  "http://example.org/browser/dom/html/test/submission_flush.html";
// This is the page pointed to by the form action in the test HTML page.
const kPostActionPage =
  "http://example.org/browser/dom/html/test/post_action_page.html";

const kFormId = "test_form";
const kFrameId = "test_frame";
const kSubmitButtonId = "submit_button";

// Take in a variety of actions (in the form of setting and unsetting form
// attributes). Then submit the form in the submit event listener to cause a
// deferred form submission. Then perform the test actions and ensure that the
// form used the correct attribute values rather than the changed ones.
async function runTest(aTestActions) {
  let tab = await BrowserTestUtils.openNewForegroundTab(gBrowser, kTestPage);
  registerCleanupFunction(() => BrowserTestUtils.removeTab(tab));

  /* eslint-disable no-shadow */
  let frame_url = await SpecialPowers.spawn(
    gBrowser.selectedBrowser,
    [{ kFormId, kFrameId, kSubmitButtonId, aTestActions }],
    async function({ kFormId, kFrameId, kSubmitButtonId, aTestActions }) {
      let form = content.document.getElementById(kFormId);

      form.addEventListener(
        "submit",
        event => {
          // Need to trigger the deferred submission by submitting in the submit
          // event handler. To prevent the form from being submitted twice, the
          // <form> tag contains the attribute |onsubmit="return false;"| to cancel
          // the original submission.
          form.submit();

          if (aTestActions.setattr) {
            for (let { attr, value } of aTestActions.setattr) {
              form.setAttribute(attr, value);
            }
          }
          if (aTestActions.unsetattr) {
            for (let attr of aTestActions.unsetattr) {
              form.removeAttribute(attr);
            }
          }
        },
        { capture: true, once: true }
      );

      // Trigger the above event listener
      content.document.getElementById(kSubmitButtonId).click();

      // Test that the form was submitted to the correct target (the frame) with
      // the correct action (kPostActionPage).
      let frame = content.document.getElementById(kFrameId);
      await new Promise(resolve => {
        frame.addEventListener("load", resolve, { once: true });
      });
      return frame.contentWindow.location.href;
    }
  );
  /* eslint-enable no-shadow */
  is(
    frame_url,
    kPostActionPage,
    "Form should have submitted with correct target and action"
  );
}

add_task(async function() {
  info("Changing action should flush pending submissions");
  await runTest({ setattr: [{ attr: "action", value: "about:blank" }] });
});

add_task(async function() {
  info("Changing target should flush pending submissions");
  await runTest({ setattr: [{ attr: "target", value: "_blank" }] });
});

add_task(async function() {
  info("Unsetting action should flush pending submissions");
  await runTest({ unsetattr: ["action"] });
});

// On failure, this test will time out rather than failing an assert. When the
// target attribute is not set, the form will submit the active page, navigating
// it away and preventing the wait for iframe load from ever finishing.
add_task(async function() {
  info("Unsetting target should flush pending submissions");
  await runTest({ unsetattr: ["target"] });
});