Install global submit listener only when amp-form extension is registered

src/document-submit.js

@@ -23,12 +23,22 @@ import {
 } from './url';
 import {Services} from './services';
 import {dev, user} from './log';
+import {getElementServiceIfAvailableForDoc} from './element-service';
 
 /**
  * @param {!./service/ampdoc-impl.AmpDoc} ampdoc
+ * @return {!Promise}
  */
 export function installGlobalSubmitListenerForDoc(ampdoc) {
-  ampdoc.getRootNode().addEventListener('submit', onDocumentFormSubmit_, true);
+  // Register global submit event listener only if the amp-form
+  // extension is used. Allowing the usage of native forms, otherwise.
+  return getElementServiceIfAvailableForDoc(ampdoc, 'amp-form', 'amp-form')
+      .then(ampFormService => {
+        if (ampFormService) {
+          ampdoc.getRootNode().addEventListener(
+              'submit', onDocumentFormSubmit_, true);
+        }
+      });
 }
 
 

test/functional/test-document-submit.js

@@ -14,8 +14,10 @@
  * limitations under the License.
  */
 
+import * as elementService from '../../src/element-service';
+import * as sinon from 'sinon';
 import {Services} from '../../src/services';
-import {onDocumentFormSubmit_} from '../../src/document-submit';
+import {installGlobalSubmitListenerForDoc, onDocumentFormSubmit_} from '../../src/document-submit';
 
 describe('test-document-submit onDocumentFormSubmit_', () => {
   let sandbox;
@@ -46,6 +48,38 @@ describe('test-document-submit onDocumentFormSubmit_', () => {
     sandbox.restore();
   });
 
+  describe('installGlobalSubmitListenerForDoc', () => {
+    let headNode;
+    let ampDoc;
+    beforeEach(() => {
+      headNode = document.createElement('body');
+      ampDoc = {
+        getRootNode: () => headNode,
+      };
+    });
+
+    afterEach(() => sandbox.reset());
+
+    it('should not register submit listener if amp-form is not registered.',
+        () => {
+          sandbox.stub(elementService, 'getElementServiceIfAvailableForDoc')
+              .returns(Promise.resolve(null));
+          sandbox.spy(headNode, 'addEventListener');
+          installGlobalSubmitListenerForDoc(ampDoc).then(() => {
+            expect(headNode.addEventListener).not.to.have.been.called;
+          });
+        });
+
+    it('should register submit listener if amp-form extension is registered.',
+        () => {
+          sandbox.stub(elementService, 'getElementServiceIfAvailableForDoc')
+              .returns(Promise.resolve({}));
+          sandbox.spy(headNode, 'addEventListener');
+          installGlobalSubmitListenerForDoc(ampDoc).then(() => {
+            expect(headNode.addEventListener).called;
+          });
+        });
+  });
 
   it('should check target and action attributes', () => {
     tgt.removeAttribute('action');