fix: Some accessibility issues (#8)

* fix: Add required attribute to checkbox & value box

* fix: Don't create iframe for every form by default

Author: notz

gwtbootstrap3/src/main/java/org/gwtbootstrap3/client/ui/CheckBox.java

@@ -21,6 +21,7 @@
  */
 
 import org.gwtbootstrap3.client.ui.base.HasFormValue;
+import org.gwtbootstrap3.client.ui.base.HasRequired;
 import org.gwtbootstrap3.client.ui.constants.Styles;
 import org.gwtbootstrap3.client.ui.gwt.ButtonBase;
 import org.gwtbootstrap3.client.ui.gwt.FormPanel;
@@ -68,7 +69,7 @@
  * </p>
  */
 public class CheckBox extends ButtonBase implements HasName, HasValue<Boolean>, HasWordWrap, HasDirectionalSafeHtml,
-        HasDirectionEstimator, IsEditor<LeafValueEditor<Boolean>>, HasFormValue, HasChangeHandlers {
+        HasDirectionEstimator, IsEditor<LeafValueEditor<Boolean>>, HasFormValue, HasChangeHandlers, HasRequired {
 
     protected final SpanElement labelElem = Document.get().createSpanElement();
     protected final InputElement inputElem;
@@ -502,4 +503,17 @@ protected void onUnload() {
         setValue(getValue());
     }
 
+    @Override
+    public void setRequired(boolean required) {
+        if (required) {
+            inputElem.setAttribute(HasRequired.REQUIRED, HasRequired.REQUIRED);
+        } else {
+            inputElem.removeAttribute(HasRequired.REQUIRED);
+        }
+    }
+
+    @Override
+    public boolean getRequired() {
+        return inputElem.hasAttribute(HasRequired.REQUIRED);
+    }
 }

gwtbootstrap3/src/main/java/org/gwtbootstrap3/client/ui/base/HasRequired.java

@@ -0,0 +1,32 @@
+package org.gwtbootstrap3.client.ui.base;
+
+/*
+ * #%L
+ * GwtBootstrap3
+ * %%
+ * Copyright (C) 2013 GwtBootstrap3
+ * %%
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * 
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * #L%
+ */
+
+/**
+ * @author Pontus Enmark
+ */
+public interface HasRequired {
+    String REQUIRED = "required";
+
+    void setRequired(boolean required);
+
+    boolean getRequired();
+}

gwtbootstrap3/src/main/java/org/gwtbootstrap3/client/ui/base/ValueBoxBase.java

@@ -44,7 +44,7 @@
 import com.google.web.bindery.event.shared.HandlerRegistration;
 
 public class ValueBoxBase<T> extends com.google.gwt.user.client.ui.ValueBoxBase<T> implements HasId, HasReadOnly,
-        HasResponsiveness, HasPlaceholder, HasAutoComplete, HasSize<InputSize>, HasEditorErrors<T>,
+        HasResponsiveness, HasPlaceholder, HasAutoComplete, HasRequired, HasSize<InputSize>, HasEditorErrors<T>,
         HasErrorHandler, HasValidators<T>, HasBlankValidator<T> {
 
     private static final String MAX_LENGTH = "maxlength";
@@ -214,4 +214,17 @@ public HandlerRegistration addValidationChangedHandler(ValidationChangedHandler
         return validatorMixin.addValidationChangedHandler(handler);
     }
 
+    @Override
+    public void setRequired(boolean required) {
+        if (required) {
+            getElement().setAttribute(HasRequired.REQUIRED, HasRequired.REQUIRED);
+        } else {
+            getElement().removeAttribute(HasRequired.REQUIRED);
+        }
+    }
+
+    @Override
+    public boolean getRequired() {
+        return getElement().hasAttribute(HasRequired.REQUIRED);
+    }
 }

gwtbootstrap3/src/main/java/org/gwtbootstrap3/client/ui/base/form/AbstractForm.java

@@ -227,7 +227,7 @@ interface IFrameTemplate extends SafeHtmlTemplates {
     private Element synthesizedFrame;
 
     public AbstractForm() {
-        this(true);
+        this(false);
     }
 
     public AbstractForm(boolean createIFrame) {