diff --git a/web_src/js/features/comp/EasyMDE.js b/web_src/js/features/comp/EasyMDE.js
index 61aaf23e89..7c1db9a998 100644
--- a/web_src/js/features/comp/EasyMDE.js
+++ b/web_src/js/features/comp/EasyMDE.js
@@ -38,6 +38,8 @@ export async function createCommentEasyMDE(textarea, easyMDEOptions = {}) {
     indentWithTabs: false,
     tabSize: 4,
     spellChecker: false,
+    inputStyle: 'contenteditable', // nativeSpellcheck requires contenteditable
+    nativeSpellcheck: true,
     toolbar: ['bold', 'italic', 'strikethrough', '|',
       'heading-1', 'heading-2', 'heading-3', 'heading-bigger', 'heading-smaller', '|',
       'code', 'quote', '|', {
diff --git a/web_src/js/features/comp/ImagePaste.js b/web_src/js/features/comp/ImagePaste.js
index 79aeffa02b..da41e7611a 100644
--- a/web_src/js/features/comp/ImagePaste.js
+++ b/web_src/js/features/comp/ImagePaste.js
@@ -1,4 +1,5 @@
 import $ from 'jquery';
+
 const {csrfToken} = window.config;
 
 async function uploadFile(file, uploadUrl) {
@@ -21,72 +22,104 @@ function clipboardPastedImages(e) {
     if (!item.type || !item.type.startsWith('image/')) continue;
     files.push(item.getAsFile());
   }
-
-  if (files.length) {
-    e.preventDefault();
-    e.stopPropagation();
-  }
   return files;
 }
 
+class TextareaEditor {
+  constructor(editor) {
+    this.editor = editor;
+  }
 
-function insertAtCursor(field, value) {
-  if (field.selectionStart || field.selectionStart === 0) {
-    const startPos = field.selectionStart;
-    const endPos = field.selectionEnd;
-    field.value = field.value.substring(0, startPos) + value + field.value.substring(endPos, field.value.length);
-    field.selectionStart = startPos + value.length;
-    field.selectionEnd = startPos + value.length;
-  } else {
-    field.value += value;
+  insertPlaceholder(value) {
+    const editor = this.editor;
+    const startPos = editor.selectionStart;
+    const endPos = editor.selectionEnd;
+    editor.value = editor.value.substring(0, startPos) + value + editor.value.substring(endPos);
+    editor.selectionStart = startPos;
+    editor.selectionEnd = startPos + value.length;
+    editor.focus();
+  }
+
+  replacePlaceholder(oldVal, newVal) {
+    const editor = this.editor;
+    const startPos = editor.selectionStart;
+    const endPos = editor.selectionEnd;
+    if (editor.value.substring(startPos, endPos) === oldVal) {
+      editor.value = editor.value.substring(0, startPos) + newVal + editor.value.substring(endPos);
+      editor.selectionEnd = startPos + newVal.length;
+    } else {
+      editor.value = editor.value.replace(oldVal, newVal);
+      editor.selectionEnd -= oldVal.length;
+      editor.selectionEnd += newVal.length;
+    }
+    editor.selectionStart = editor.selectionEnd;
+    editor.focus();
   }
 }
 
-function replaceAndKeepCursor(field, oldval, newval) {
-  if (field.selectionStart || field.selectionStart === 0) {
-    const startPos = field.selectionStart;
-    const endPos = field.selectionEnd;
-    field.value = field.value.replace(oldval, newval);
-    field.selectionStart = startPos + newval.length - oldval.length;
-    field.selectionEnd = endPos + newval.length - oldval.length;
-  } else {
-    field.value = field.value.replace(oldval, newval);
+class CodeMirrorEditor {
+  constructor(editor) {
+    this.editor = editor;
+  }
+
+  insertPlaceholder(value) {
+    const editor = this.editor;
+    const startPoint = editor.getCursor('start');
+    const endPoint = editor.getCursor('end');
+    editor.replaceSelection(value);
+    endPoint.ch = startPoint.ch + value.length;
+    editor.setSelection(startPoint, endPoint);
+    editor.focus();
+  }
+
+  replacePlaceholder(oldVal, newVal) {
+    const editor = this.editor;
+    const endPoint = editor.getCursor('end');
+    if (editor.getSelection() === oldVal) {
+      editor.replaceSelection(newVal);
+    } else {
+      editor.setValue(editor.getValue().replace(oldVal, newVal));
+    }
+    endPoint.ch -= oldVal.length;
+    endPoint.ch += newVal.length;
+    editor.setSelection(endPoint, endPoint);
+    editor.focus();
   }
 }
 
-export function initCompImagePaste($target) {
-  $target.each(function () {
-    const dropzone = this.querySelector('.dropzone');
-    if (!dropzone) {
+
+export function initEasyMDEImagePaste(easyMDE, $dropzone) {
+  const uploadUrl = $dropzone.attr('data-upload-url');
+  const $files = $dropzone.find('.files');
+
+  if (!uploadUrl || !$files.length) return;
+
+  const uploadClipboardImage = async (editor, e) => {
+    const pastedImages = clipboardPastedImages(e);
+    if (!pastedImages || pastedImages.length === 0) {
       return;
     }
-    const uploadUrl = dropzone.getAttribute('data-upload-url');
-    const dropzoneFiles = dropzone.querySelector('.files');
-    for (const textarea of this.querySelectorAll('textarea')) {
-      textarea.addEventListener('paste', async (e) => {
-        for (const img of clipboardPastedImages(e)) {
-          const name = img.name.slice(0, img.name.lastIndexOf('.'));
-          insertAtCursor(textarea, `![${name}]()`);
-          const data = await uploadFile(img, uploadUrl);
-          replaceAndKeepCursor(textarea, `![${name}]()`, `![${name}](/attachments/${data.uuid})`);
-          const input = $(`<input id="${data.uuid}" name="files" type="hidden">`).val(data.uuid);
-          dropzoneFiles.appendChild(input[0]);
-        }
-      }, false);
-    }
-  });
-}
+    e.preventDefault();
+    e.stopPropagation();
 
-export function initEasyMDEImagePaste(easyMDE, dropzone, files) {
-  const uploadUrl = dropzone.getAttribute('data-upload-url');
-  easyMDE.codemirror.on('paste', async (_, e) => {
-    for (const img of clipboardPastedImages(e)) {
+    for (const img of pastedImages) {
       const name = img.name.slice(0, img.name.lastIndexOf('.'));
+
+      const placeholder = `![${name}](uploading ...)`;
+      editor.insertPlaceholder(placeholder);
       const data = await uploadFile(img, uploadUrl);
-      const pos = easyMDE.codemirror.getCursor();
-      easyMDE.codemirror.replaceRange(`![${name}](/attachments/${data.uuid})`, pos);
-      const input = $(`<input id="${data.uuid}" name="files" type="hidden">`).val(data.uuid);
-      files.append(input);
+      editor.replacePlaceholder(placeholder, `![${name}](/attachments/${data.uuid})`);
+
+      const $input = $(`<input name="files" type="hidden">`).attr('id', data.uuid).val(data.uuid);
+      $files.append($input);
     }
+  };
+
+  easyMDE.codemirror.on('paste', async (_, e) => {
+    return uploadClipboardImage(new CodeMirrorEditor(easyMDE.codemirror), e);
+  });
+
+  $(easyMDE.element).on('paste', async (e) => {
+    return uploadClipboardImage(new TextareaEditor(easyMDE.element), e.originalEvent);
   });
 }
diff --git a/web_src/js/features/repo-issue.js b/web_src/js/features/repo-issue.js
index bdd616f071..12900c2455 100644
--- a/web_src/js/features/repo-issue.js
+++ b/web_src/js/features/repo-issue.js
@@ -2,7 +2,7 @@ import $ from 'jquery';
 import {htmlEscape} from 'escape-goat';
 import attachTribute from './tribute.js';
 import {createCommentEasyMDE, getAttachedEasyMDE} from './comp/EasyMDE.js';
-import {initCompImagePaste} from './comp/ImagePaste.js';
+import {initEasyMDEImagePaste} from './comp/ImagePaste.js';
 import {initCompMarkupContentPreviewTab} from './comp/MarkupContentPreview.js';
 
 const {appSubUrl, csrfToken} = window.config;
@@ -480,8 +480,9 @@ export function initRepoPullRequestReview() {
       // the editor's height is too large in some cases, and the panel cannot be scrolled with page now because there is `.repository .diff-detail-box.sticky { position: sticky; }`
       // the temporary solution is to make the editor's height smaller (about 4 lines). GitHub also only show 4 lines for default. We can improve the UI (including Dropzone area) in future
       // EasyMDE's options can not handle minHeight & maxHeight together correctly, we have to set max-height for .CodeMirror-scroll in CSS.
-      await createCommentEasyMDE($reviewBox.find('textarea'), {minHeight: '80px'});
-      initCompImagePaste($reviewBox);
+      const $reviewTextarea = $reviewBox.find('textarea');
+      const easyMDE = await createCommentEasyMDE($reviewTextarea, {minHeight: '80px'});
+      initEasyMDEImagePaste(easyMDE, $reviewBox.find('.dropzone'));
     })();
   }
 
diff --git a/web_src/js/features/repo-legacy.js b/web_src/js/features/repo-legacy.js
index 2bf80d5511..11c97ccfb0 100644
--- a/web_src/js/features/repo-legacy.js
+++ b/web_src/js/features/repo-legacy.js
@@ -1,7 +1,7 @@
 import $ from 'jquery';
 import {createCommentEasyMDE, getAttachedEasyMDE} from './comp/EasyMDE.js';
 import {initCompMarkupContentPreviewTab} from './comp/MarkupContentPreview.js';
-import {initCompImagePaste, initEasyMDEImagePaste} from './comp/ImagePaste.js';
+import {initEasyMDEImagePaste} from './comp/ImagePaste.js';
 import {
   initRepoIssueBranchSelect, initRepoIssueCodeCommentCancel,
   initRepoIssueCommentDelete,
@@ -33,7 +33,8 @@ import initRepoPullRequestMergeForm from './repo-issue-pr-form.js';
 const {csrfToken} = window.config;
 
 export function initRepoCommentForm() {
-  if ($('.comment.form').length === 0) {
+  const $commentForm = $('.comment.form');
+  if ($commentForm.length === 0) {
     return;
   }
 
@@ -67,12 +68,13 @@ export function initRepoCommentForm() {
   }
 
   (async () => {
-    await createCommentEasyMDE($('.comment.form textarea:not(.review-textarea)'));
-    initCompImagePaste($('.comment.form'));
+    const $textarea = $commentForm.find('textarea:not(.review-textarea)');
+    const easyMDE = await createCommentEasyMDE($textarea);
+    initEasyMDEImagePaste(easyMDE, $commentForm.find('.dropzone'));
   })();
 
   initBranchSelector();
-  initCompMarkupContentPreviewTab($('.comment.form'));
+  initCompMarkupContentPreviewTab($commentForm);
 
   // List submits
   function initListSubmits(selector, outerSelector) {
@@ -352,9 +354,7 @@ async function onEditContent(event) {
     easyMDE = await createCommentEasyMDE($textarea);
 
     initCompMarkupContentPreviewTab($editContentForm);
-    if ($dropzone.length === 1) {
-      initEasyMDEImagePaste(easyMDE, $dropzone[0], $dropzone.find('.files'));
-    }
+    initEasyMDEImagePaste(easyMDE, $dropzone);
 
     const $saveButton = $editContentZone.find('.save.button');
     $textarea.on('ce-quick-submit', () => {
diff --git a/web_src/js/features/repo-release.js b/web_src/js/features/repo-release.js
index a44b91f35b..b68a7a6cd5 100644
--- a/web_src/js/features/repo-release.js
+++ b/web_src/js/features/repo-release.js
@@ -23,10 +23,9 @@ export function initRepoReleaseEditor() {
   (async () => {
     const $textarea = $editor.find('textarea');
     await attachTribute($textarea.get(), {mentions: false, emoji: true});
-    const $files = $editor.parent().find('.files');
     const easyMDE = await createCommentEasyMDE($textarea);
     initCompMarkupContentPreviewTab($editor);
-    const dropzone = $editor.parent().find('.dropzone')[0];
-    initEasyMDEImagePaste(easyMDE, dropzone, $files);
+    const $dropzone = $editor.parent().find('.dropzone');
+    initEasyMDEImagePaste(easyMDE, $dropzone);
   })();
 }
diff --git a/web_src/js/features/repo-wiki.js b/web_src/js/features/repo-wiki.js
index 27f44f4e22..4555b32e5f 100644
--- a/web_src/js/features/repo-wiki.js
+++ b/web_src/js/features/repo-wiki.js
@@ -67,6 +67,8 @@ async function initRepoWikiFormEditor() {
     indentWithTabs: false,
     tabSize: 4,
     spellChecker: false,
+    inputStyle: 'contenteditable', // nativeSpellcheck requires contenteditable
+    nativeSpellcheck: true,
     toolbar: ['bold', 'italic', 'strikethrough', '|',
       'heading-1', 'heading-2', 'heading-3', 'heading-bigger', 'heading-smaller', '|',
       {