const { PromptTestUtils } = ChromeUtils.importESModule( "resource://testing-common/PromptTestUtils.sys.mjs" ); function pageScript() { window.addEventListener( "beforeunload", function (event) { var str = "Some text that causes the beforeunload dialog to be shown"; event.returnValue = str; return str; }, true ); } SpecialPowers.pushPrefEnv({ set: [["dom.require_user_interaction_for_beforeunload", false]], }); const PAGE_URL = "data:text/html," + encodeURIComponent(""); add_task(async function enableDialogs() { // The onbeforeunload dialog should appear. let dialogPromise = PromptTestUtils.waitForPrompt(null, { modalType: Services.prompt.MODAL_TYPE_CONTENT, promptType: "confirmEx", }); let openPagePromise = openPage(true); let dialog = await dialogPromise; Assert.ok(true, "Showed the beforeunload dialog."); await PromptTestUtils.handlePrompt(dialog, { buttonNumClick: 0 }); await openPagePromise; }); add_task(async function disableDialogs() { // The onbeforeunload dialog should NOT appear. await openPage(false); info("If we time out here, then the dialog was shown..."); }); async function openPage(enableDialogs) { // Open about:blank in a new tab. await BrowserTestUtils.withNewTab( { gBrowser, url: "about:blank" }, async function (browser) { // Load the page. BrowserTestUtils.startLoadingURIString(browser, PAGE_URL); await BrowserTestUtils.browserLoaded(browser); // Load the content script in the frame. let methodName = enableDialogs ? "enableDialogs" : "disableDialogs"; await SpecialPowers.spawn(browser, [methodName], async function (name) { content.windowUtils[name](); }); // And then navigate away. BrowserTestUtils.startLoadingURIString(browser, "http://example.com/"); await BrowserTestUtils.browserLoaded(browser); } ); }