take care of referencing form elements

Author: rbri

src/changes/changes.xml

@@ -21,7 +21,7 @@
                 Upgrade Apache commons-io to 2.14.0.
             </action>
             <action type="fix" dev="rbri">
-                Form elements are all elements that belong to a form; not only the child elements. We now 
+                Form elements are all elements that belong to a form; not only the child elements. We now
                 take care of elements that use the form attribute to specify the associated form in many more places.
             </action>
             <action type="add" dev="Lai Quang Duong">

src/main/java/org/htmlunit/html/HtmlButton.java

@@ -15,7 +15,6 @@
 package org.htmlunit.html;
 
 import static org.htmlunit.BrowserVersionFeatures.EVENT_MOUSE_ON_DISABLED;
-import static org.htmlunit.BrowserVersionFeatures.FORM_FORM_ATTRIBUTE_SUPPORTED;
 import static org.htmlunit.BrowserVersionFeatures.HTMLBUTTON_SUBMIT_IGNORES_DISABLED_STATE;
 import static org.htmlunit.BrowserVersionFeatures.HTMLBUTTON_WILL_VALIDATE_IGNORES_READONLY;
 import static org.htmlunit.html.HtmlForm.ATTRIBUTE_FORMNOVALIDATE;
@@ -92,18 +91,7 @@ public void setValueAttribute(final String newValue) {
     @Override
     protected boolean doClickStateUpdate(final boolean shiftKey, final boolean ctrlKey) throws IOException {
         if (hasFeature(HTMLBUTTON_SUBMIT_IGNORES_DISABLED_STATE) || !isDisabled()) {
-            HtmlForm form = null;
-            final String formId = getAttributeDirect("form");
-            if (DomElement.ATTRIBUTE_NOT_DEFINED == formId || !hasFeature(FORM_FORM_ATTRIBUTE_SUPPORTED)) {
-                form = getEnclosingForm();
-            }
-            else {
-                final DomElement elem = getHtmlPageOrNull().getElementById(formId);
-                if (elem instanceof HtmlForm) {
-                    form = (HtmlForm) elem;
-                }
-            }
-
+            final HtmlForm form = getEnclosingForm();
             if (form != null) {
                 final String type = getType();
                 if (TYPE_BUTTON.equals(type)) {

src/main/java/org/htmlunit/html/HtmlForm.java

@@ -600,36 +600,17 @@ private <E extends HtmlElement> List<E> getFormElementsByAttribute(
     public List<HtmlElement> getElements() {
         final List<HtmlElement> elements = new ArrayList<>();
 
-        final String formId = getId();
-        final boolean formAttribSupported = formId != ATTRIBUTE_NOT_DEFINED
-                && getPage().getWebClient().getBrowserVersion().hasFeature(FORM_FORM_ATTRIBUTE_SUPPORTED);
-
-        final HashSet<HtmlElement> nestedForms = new HashSet<>();
-
         for (final HtmlElement element : ((HtmlPage) getPage()).getBody().getHtmlElementDescendants()) {
-            if (element != this && element instanceof HtmlForm && this.isAncestorOf(element)) {
-                nestedForms.add(element);
-                continue;
-            }
-
-            if (SUBMITTABLE_ELEMENT_NAMES.contains(element.getTagName())) {
-                if (isAncestorOf(element)) {
-                    elements.add(element);
-                    continue;
-                }
-
-                if (formAttribSupported) {
-                    final String formIdRef = element.getAttribute("form");
-                    if (formId.equals(formIdRef)) {
-                        elements.add(element);
-                        continue;
-                    }
-                }
+            if (SUBMITTABLE_ELEMENT_NAMES.contains(element.getTagName())
+                    && element.getEnclosingForm() == this) {
+                elements.add(element);
             }
         }
 
         for (final HtmlElement element : lostChildren_) {
-            if (SUBMITTABLE_ELEMENT_NAMES.contains(element.getTagName())) {
+            if (SUBMITTABLE_ELEMENT_NAMES.contains(element.getTagName())
+                    && element.getEnclosingForm() == this
+                    && !elements.contains(element)) {
                 elements.add(element);
             }
         }

src/main/java/org/htmlunit/javascript/host/html/HTMLFormElement.java

@@ -133,7 +133,6 @@ protected Object getWithPreemption(final String name) {
                         return new ArrayList<>();
                     }
                     response.addAll(((HtmlForm) domNode).getElements());
-                    response.addAll(htmlForm.getLostChildren());
                     return response;
                 });
 

src/test/java/org/htmlunit/html/parser/MalformedHtmlTest.java

@@ -23,6 +23,7 @@
 import org.htmlunit.html.HtmlPageTest;
 import org.htmlunit.junit.BrowserRunner;
 import org.htmlunit.junit.BrowserRunner.Alerts;
+import org.htmlunit.junit.BrowserRunner.HtmlUnitNYI;
 import org.htmlunit.junit.BrowserRunner.NotYetImplemented;
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -965,7 +966,7 @@ public void formInTable8() throws Exception {
     @Test
     @Alerts(DEFAULT = {"3", "1b", "1a", "1c", "0", "TABLE"},
             IE = {"3", "1a", "1b", "1c", "0", "TABLE"})
-    @NotYetImplemented({CHROME, EDGE, FF, FF_ESR})
+    @HtmlUnitNYI(IE = {"3", "1b", "1a", "1c", "0", "TABLE"})
     public void formInTable9() throws Exception {
         final String html = "<html>\n"
                 + "<body>\n"