From f5294c75cd0c6667095589abd39b01211d3fdedf Mon Sep 17 00:00:00 2001
From: Rias <hey@rias.be>
Date: Thu, 1 Oct 2026 10:09:28 +0200
Subject: [PATCH 1/2] Add reusable server form modals

Co-authored-by: Nathaniel Hammond <nathaniel@pixelandtonic.com>
---
 CHANGELOG.md                                  |   1 +
 .../composables/useElementActionMenu.ts       |  18 +++
 resources/js/modules/forms/FormModal.vue      | 111 ++++++++++++++++++
 resources/js/modules/forms/open-form-modal.ts |  60 ++++++++++
 4 files changed, 190 insertions(+)
 create mode 100644 resources/js/modules/forms/FormModal.vue
 create mode 100644 resources/js/modules/forms/open-form-modal.ts

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3adee70813c..f7b0eebcb0c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -27,6 +27,7 @@
 - Improved the styling of control panel tables and lightswitches. ([#19766](https://github.com/craftcms/cms/pull/19766))
 - Improved disabled secondary form actions with explanatory tooltips.
 - The “Assets” system settings nav item is now listed under “Content”, and “Globals”, “Categories”, and “Tags” are now listed under a new “Deprecated” heading, if those concepts are supported for the project. ([#19670](https://github.com/craftcms/cms/pull/19670))
+- Added reusable server-built form modals and the `formModal` element action behavior.
 - Added the `<craft-timeline-item>` web component. ([#19629](https://github.com/craftcms/cms/pull/19629))
 - Added the `placeholder` property to `<craft-thumbnail>`, for an image to show while the thumbnail loads. ([#19750](https://github.com/craftcms/cms/pull/19750))
 - Added the `--c-thumbnail-image-radius` custom property to `<craft-thumbnail>`, and its other custom properties can now be set on an ancestor. ([#19758](https://github.com/craftcms/cms/pull/19758))
diff --git a/resources/js/modules/elements/composables/useElementActionMenu.ts b/resources/js/modules/elements/composables/useElementActionMenu.ts
index 825591458e3..fa29f7009c5 100644
--- a/resources/js/modules/elements/composables/useElementActionMenu.ts
+++ b/resources/js/modules/elements/composables/useElementActionMenu.ts
@@ -7,6 +7,7 @@ import {openSlideout, type SlideoutController} from '@/common/slideouts';
 import type {ActionItem} from '@/common/types';
 import {ElementDeletionManager} from '@/modules/element-deletion-manager';
 import type {FormProperties, FormValues} from '@/modules/forms/types';
+import {openFormModal} from '@/modules/forms/open-form-modal';
 import {
   openImageEditorDialog,
   type ImageEditorSettings,
@@ -52,6 +53,13 @@ export type ElementActionBehavior =
       url: string;
       entryTypeFromField?: boolean;
     }
+  /** Loads and submits a server-built form, then reloads the page. */
+  | {
+      type: 'formModal';
+      modalUrl: string;
+      actionUrl: string;
+      params?: FormValues;
+    }
   // The asset behaviors below all hand off to a modal or uploader, and reload
   // the page afterwards rather than patching the file's details into it.
   | {
@@ -200,6 +208,16 @@ export function createElementActionMenu({
         return;
       }
 
+      case 'formModal':
+        void openFormModal({
+          modalUrl: behavior.modalUrl,
+          actionUrl: behavior.actionUrl,
+          params: behavior.params,
+          onSubmitted: () => router.reload(),
+        });
+
+        return;
+
       case 'previewFile':
         new Craft.PreviewFileModal(behavior.assetId, behavior.settings ?? {});
 
diff --git a/resources/js/modules/forms/FormModal.vue b/resources/js/modules/forms/FormModal.vue
new file mode 100644
index 00000000000..951f1e77ec6
--- /dev/null
+++ b/resources/js/modules/forms/FormModal.vue
@@ -0,0 +1,111 @@
+<script setup lang="ts">
+  import {actionClient, t} from '@craftcms/ui';
+  import {onMounted, shallowRef, useTemplateRef} from 'vue';
+  import ModalForm from '@/common/components/ModalForm.vue';
+  import FormRenderer from './FormRenderer.vue';
+  import type {FormPayload, FormValues} from './types';
+
+  export interface FormModalResponse {
+    form: FormPayload;
+    title?: string | null;
+    submitLabel?: string | null;
+  }
+
+  const props = withDefaults(
+    defineProps<{
+      modalUrl: string;
+      actionUrl: string;
+      params?: FormValues;
+      /** Used when the server doesn't send a title. */
+      title?: string;
+      /** Used when the server doesn't send a submit label. */
+      submitLabel?: string;
+      width?: string;
+    }>(),
+    {
+      params: () => ({}),
+      title: undefined,
+      submitLabel: () => t('Save'),
+      width: 'md',
+    }
+  );
+
+  const emit = defineEmits<{
+    (event: 'close'): void;
+    (event: 'submitted', data: Record<string, unknown>): void;
+  }>();
+
+  const modal = shallowRef<FormModalResponse | null>(null);
+  const errors = shallowRef<FormPayload['errors']>([]);
+  const loading = shallowRef(false);
+  const renderer =
+    useTemplateRef<InstanceType<typeof FormRenderer>>('renderer');
+
+  onMounted(async () => {
+    try {
+      const {data} = await actionClient.get<FormModalResponse>(props.modalUrl, {
+        params: props.params,
+      });
+      errors.value = data.form.errors ?? [];
+      modal.value = data;
+    } catch (error: any) {
+      Craft.cp?.displayError?.(
+        error?.response?.data?.message ?? t('A server error occurred.')
+      );
+      emit('close');
+    }
+  });
+
+  async function submit(): Promise<void> {
+    if (!renderer.value || loading.value || !renderer.value.canSubmit()) {
+      return;
+    }
+
+    loading.value = true;
+    errors.value = [];
+
+    try {
+      const {data} = await actionClient.post<Record<string, unknown>>(
+        props.actionUrl,
+        {...renderer.value.currentValues(), ...props.params}
+      );
+
+      if (typeof data?.message === 'string') {
+        Craft.cp?.displayNotice?.(data.message);
+      }
+
+      emit('submitted', data ?? {});
+    } catch (error: any) {
+      const responseErrors: Record<string, string | string[]> =
+        error?.response?.data?.errors ?? {};
+      errors.value = Object.entries(responseErrors).map(([path, messages]) => ({
+        path: path.split('.'),
+        messages: Array.isArray(messages) ? messages : [messages],
+      }));
+      Craft.cp?.displayError?.(
+        error?.response?.data?.message ?? t('A server error occurred.')
+      );
+    } finally {
+      loading.value = false;
+    }
+  }
+</script>
+
+<template>
+  <ModalForm
+    :is-active="modal !== null"
+    :title="modal?.title ?? title"
+    :submit-label="modal?.submitLabel ?? submitLabel"
+    :loading="loading"
+    :width="width"
+    @close="emit('close')"
+    @submit="submit"
+  >
+    <FormRenderer
+      v-if="modal"
+      ref="renderer"
+      :payload="modal.form"
+      :errors="errors"
+    />
+  </ModalForm>
+</template>
diff --git a/resources/js/modules/forms/open-form-modal.ts b/resources/js/modules/forms/open-form-modal.ts
new file mode 100644
index 00000000000..1b9992b5e3b
--- /dev/null
+++ b/resources/js/modules/forms/open-form-modal.ts
@@ -0,0 +1,60 @@
+import type {App} from 'vue';
+import type {FormValues} from './types';
+
+export interface FormModalOptions {
+  modalUrl: string;
+  actionUrl: string;
+  params?: FormValues;
+  title?: string;
+  submitLabel?: string;
+  width?: string;
+  onSubmitted?: (data: Record<string, unknown>) => void;
+}
+
+/**
+ * Opens a server-built form in a detached Vue app with registered CP controls.
+ * The app, host, and registry installation are removed on close or submission.
+ */
+export async function openFormModal({
+  onSubmitted,
+  ...props
+}: FormModalOptions): Promise<void> {
+  const [{createApp, h}, {default: FormModal}, {cpComponentRegistry}] =
+    await Promise.all([
+      import('vue'),
+      import('./FormModal.vue'),
+      import('@/bootstrap/components'),
+    ]);
+
+  const host = document.createElement('div');
+  document.body.append(host);
+
+  let closed = false;
+  const close = () => {
+    if (closed) {
+      return;
+    }
+
+    closed = true;
+    app.unmount();
+    host.remove();
+  };
+
+  const app: App = createApp({
+    render: () =>
+      h(FormModal, {
+        ...props,
+        onClose: close,
+        onSubmitted: (data: Record<string, unknown>) => {
+          close();
+          onSubmitted?.(data);
+        },
+      }),
+  });
+
+  cpComponentRegistry.install(app);
+  app.onUnmount(() => cpComponentRegistry.uninstall(app));
+  app.config.compilerOptions.isCustomElement = (tag: string) =>
+    tag.includes('-');
+  app.mount(host);
+}

From a910be6e3874da3183a3eaf24647fefeb3ee1bc8 Mon Sep 17 00:00:00 2001
From: Rias <hey@rias.be>
Date: Thu, 1 Oct 2026 10:09:46 +0200
Subject: [PATCH 2/2] Reference server form modal PR in changelog

Co-authored-by: Nathaniel Hammond <nathaniel@pixelandtonic.com>
---
 CHANGELOG.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index f7b0eebcb0c..389b1501600 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -27,7 +27,7 @@
 - Improved the styling of control panel tables and lightswitches. ([#19766](https://github.com/craftcms/cms/pull/19766))
 - Improved disabled secondary form actions with explanatory tooltips.
 - The “Assets” system settings nav item is now listed under “Content”, and “Globals”, “Categories”, and “Tags” are now listed under a new “Deprecated” heading, if those concepts are supported for the project. ([#19670](https://github.com/craftcms/cms/pull/19670))
-- Added reusable server-built form modals and the `formModal` element action behavior.
+- Added reusable server-built form modals and the `formModal` element action behavior. ([#19768](https://github.com/craftcms/cms/pull/19768))
 - Added the `<craft-timeline-item>` web component. ([#19629](https://github.com/craftcms/cms/pull/19629))
 - Added the `placeholder` property to `<craft-thumbnail>`, for an image to show while the thumbnail loads. ([#19750](https://github.com/craftcms/cms/pull/19750))
 - Added the `--c-thumbnail-image-radius` custom property to `<craft-thumbnail>`, and its other custom properties can now be set on an ancestor. ([#19758](https://github.com/craftcms/cms/pull/19758))