Add (Client) Functions as Form Actions

packages/react-dom-bindings/src/events/plugins/FormActionEventPlugin.js

@@ -44,7 +44,10 @@ function extractEvents(
     (nativeEvent: any).submitter;
   let submitterAction;
   if (submitter) {
-    submitterAction = (getFiberCurrentPropsFromNode(submitter): any).formAction;
+    const submitterProps = getFiberCurrentPropsFromNode(submitter);
+    submitterAction = submitterProps
+      ? (submitterProps: any).formAction
+      : submitter.getAttribute('formAction');
     if (submitterAction != null) {
       // The submitter overrides the form action.
       action = submitterAction;

packages/react-dom/src/__tests__/ReactDOMForm-test.js

@@ -414,4 +414,40 @@ describe('ReactDOMForm', () => {
     expect(nav).toBe('Navigate to: http://example.com/submit');
     expect(actionCalled).toBe(false);
   });
+
+  // @gate enableFormActions || !__DEV__
+  it('allows a non-react html formaction to be invoked', async () => {
+    let actionCalled = false;
+
+    function action(formData) {
+      actionCalled = true;
+    }
+
+    const root = ReactDOMClient.createRoot(container);
+    await act(async () => {
+      root.render(
+        <form
+          action={action}
+          dangerouslySetInnerHTML={{
+            __html: `
+            <input
+              type="submit"
+              formAction="http://example.com/submit"
+            />
+          `,
+          }}
+        />,
+      );
+    });
+
+    const node = container.getElementsByTagName('input')[0];
+    let nav;
+    try {
+      submit(node);
+    } catch (x) {
+      nav = x.message;
+    }
+    expect(nav).toBe('Navigate to: http://example.com/submit');
+    expect(actionCalled).toBe(false);
+  });
 });