Remove SubmitEvent polyfill (#37276)

Remove this obsolete polyfill as per
https://github.com/go-gitea/gitea/pull/37270#issuecomment-4273399551.

Co-authored-by: Claude (Opus 4.7) <noreply@anthropic.com>

web_src/js/features/common-fetch-action.ts

@@ -1,6 +1,6 @@
 import {GET, request} from '../modules/fetch.ts';
 import {hideToastsAll, showErrorToast} from '../modules/toast.ts';
-import {addDelegatedEventListener, createElementFromHTML, submitEventSubmitter} from '../utils/dom.ts';
+import {addDelegatedEventListener, createElementFromHTML} from '../utils/dom.ts';
 import {confirmModal, createConfirmModal} from './comp/ConfirmModal.ts';
 import {ignoreAreYouSure} from '../vendor/jquery.are-you-sure.ts';
 import {registerGlobalSelectorFunc} from '../modules/observer.ts';
@@ -146,7 +146,7 @@ async function performActionRequest(el: HTMLElement, opt: FetchActionOpts) {
 }
 
 type SubmitFormFetchActionOpts = {
-  formSubmitter?: HTMLElement;
+  formSubmitter?: HTMLElement | null;
   formData?: FormData;
 };
 
@@ -396,10 +396,10 @@ export function initGlobalFetchAction() {
   //   * it has "-header" and "-content" variants to set the header and content of the "confirm modal"
   //   * it can refer an existing modal element by "#the-modal-id"
 
-  addDelegatedEventListener(document, 'submit', '.form-fetch-action', async (el: HTMLFormElement, e) => {
+  addDelegatedEventListener<HTMLFormElement, SubmitEvent>(document, 'submit', '.form-fetch-action', async (el, e) => {
     // "fetch-action" will use the form's data to send the request
     e.preventDefault();
-    await submitFormFetchAction(el, {formSubmitter: submitEventSubmitter(e)});
+    await submitFormFetchAction(el, {formSubmitter: e.submitter});
   });
 
   addDelegatedEventListener(document, 'click', '.link-action', async (el, e) => {

web_src/js/features/repo-diff.ts

@@ -5,7 +5,7 @@ import {validateTextareaNonEmpty} from './comp/ComboMarkdownEditor.ts';
 import {initViewedCheckboxListenerFor, initExpandAndCollapseFilesButton} from './pull-view-file.ts';
 import {initImageDiff} from './imagediff.ts';
 import {showErrorToast} from '../modules/toast.ts';
-import {submitEventSubmitter, queryElemSiblings, hideElem, showElem, animateOnce, addDelegatedEventListener, createElementFromHTML, queryElems} from '../utils/dom.ts';
+import {queryElemSiblings, hideElem, showElem, animateOnce, addDelegatedEventListener, createElementFromHTML, queryElems} from '../utils/dom.ts';
 import {POST, GET} from '../modules/fetch.ts';
 import {createTippy} from '../modules/tippy.ts';
 import {invertFileFolding} from './file-fold.ts';
@@ -41,8 +41,8 @@ function initRepoDiffConversationForm() {
       const formData = new FormData(form);
 
       // if the form is submitted by a button, append the button's name and value to the form data
-      const submitter = submitEventSubmitter(e);
+      const submitter = e.submitter;
-      const isSubmittedByButton = (submitter?.nodeName === 'BUTTON') || (submitter?.nodeName === 'INPUT' && submitter.type === 'submit');
+      const isSubmittedByButton = submitter instanceof HTMLButtonElement || (submitter instanceof HTMLInputElement && submitter.type === 'submit');
       if (isSubmittedByButton && submitter.name) {
         formData.append(submitter.name, submitter.value);
       }

web_src/js/index.ts

@@ -45,7 +45,6 @@ import {initCaptcha} from './features/captcha.ts';
 import {initRepositoryActionView} from './features/repo-actions.ts';
 import {initGlobalTooltips} from './modules/tippy.ts';
 import {initGiteaFomantic} from './modules/fomantic.ts';
-import {initSubmitEventPolyfill} from './utils/dom.ts';
 import {initRepoIssueList} from './features/repo-issue-list.ts';
 import {initCommonIssueListQuickGoto} from './features/common-issue-list.ts';
 import {initRepoContributors} from './features/contributors.ts';
@@ -69,7 +68,6 @@ import {initDevtest} from './modules/devtest.ts';
 
 const initStartTime = performance.now();
 const initPerformanceTracer = callInitFunctions([
-  initSubmitEventPolyfill,
   initGiteaFomantic,
 
   initGlobalComponent,

web_src/js/utils/dom.ts

@@ -257,28 +257,6 @@ export function loadElem(el: LoadableElement, src: string) {
   });
 }
 
-// some browsers like PaleMoon don't have "SubmitEvent" support, so polyfill it by a tricky method: use the last clicked button as submitter
-// it can't use other transparent polyfill patches because PaleMoon also doesn't support "addEventListener(capture)"
-const needSubmitEventPolyfill = typeof SubmitEvent === 'undefined';
-
-export function submitEventSubmitter(e: any) {
-  e = e.originalEvent ?? e; // if the event is wrapped by jQuery, use "originalEvent", otherwise, use the event itself
-  return needSubmitEventPolyfill ? (e.target._submitter || null) : e.submitter;
-}
-
-function submitEventPolyfillListener(e: Event) {
-  const form = (e.target as HTMLElement).closest('form');
-  if (!form) return;
-  form._submitter = (e.target as HTMLElement).closest('button:not([type]), button[type="submit"], input[type="submit"]');
-}
-
-export function initSubmitEventPolyfill() {
-  if (!needSubmitEventPolyfill) return;
-  console.warn(`This browser doesn't have "SubmitEvent" support, use a tricky method to polyfill`);
-  document.body.addEventListener('click', submitEventPolyfillListener);
-  document.body.addEventListener('focus', submitEventPolyfillListener);
-}
-
 export function isElemVisible(el: HTMLElement): boolean {
   // Check if an element is visible, equivalent to jQuery's `:visible` pseudo.
   // This function DOESN'T account for all possible visibility scenarios, its behavior is covered by the tests of "querySingleVisibleElem"