add some comments

Author: rbri

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

@@ -77,7 +77,10 @@ protected BaseFrameElement(final String qualifiedName, final SgmlPage page,
             // if created by the HTMLParser the src attribute is not set via setAttribute() or some other method but is
             // part of the given attributes already.
             final String src = getSrcAttribute();
-            if (ATTRIBUTE_NOT_DEFINED != src && !UrlUtils.ABOUT_BLANK.equals(src)) {
+
+            // src-less IFrame or src='about:blank'
+            // these are loaded sync
+            if (ATTRIBUTE_NOT_DEFINED != src && !UrlUtils.ABOUT_BLANK.equals(src.trim())) {
                 loadSrcWhenAddedToPage_ = true;
             }
         }

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

@@ -261,12 +261,14 @@ public void initialize() throws IOException, FailingHttpStatusCodeException {
             executeEventHandlersIfNeeded(Event.TYPE_READY_STATE_CHANGE);
         }
 
-        executePostponedScriptsIfNeeded();
-
         executeDeferredScriptsIfNeeded();
 
         executeEventHandlersIfNeeded(Event.TYPE_DOM_DOCUMENT_LOADED);
 
+        // postponed actions are more or less the async scripts,
+        // they are running in real browsers whenever the download is done
+        processPostponedActionsIfNeeded();
+
         loadFrames();
 
         // don't set the ready state if we really load the blank page into the window
@@ -1480,7 +1482,7 @@ private String getRefreshStringOrNull() {
         return getWebResponse().getResponseHeaderValue("Refresh");
     }
 
-    private void executePostponedScriptsIfNeeded() {
+    private void processPostponedActionsIfNeeded() {
         if (!getWebClient().isJavaScriptEnabled()) {
             return;
         }

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

@@ -84,6 +84,8 @@ public static void onAllChildrenAddedToPage(final ScriptElement script, final bo
         final String srcAttrib = script.getScriptSource();
         final boolean hasNoSrcAttrib = ATTRIBUTE_NOT_DEFINED == srcAttrib;
         if (!hasNoSrcAttrib && script.isDeferred()) {
+            // HtmlPage.executeDeferredScriptsIfNeeded() will process these
+            // directly after the load
             return;
         }