diff --git a/reference/dom/domdocument.xml b/reference/dom/domdocument.xml
index ca359f1f9b..5a9eb7354b 100644
--- a/reference/dom/domdocument.xml
+++ b/reference/dom/domdocument.xml
@@ -66,7 +66,7 @@
     </fieldsynopsis>
     <fieldsynopsis>
      <modifier>public</modifier>
-     <type>string</type>
+     <type class="union"><type>string</type><type>null</type></type>
      <varname linkend="domdocument.props.documenturi">documentURI</varname>
     </fieldsynopsis>
     <fieldsynopsis>
@@ -131,7 +131,7 @@
     <fieldsynopsis>
      <modifier>public</modifier>
      <modifier>readonly</modifier>
-     <type>string</type>
+     <type class="union"><type>string</type><type>null</type></type>
      <varname linkend="domdocument.props.xmlencoding">xmlEncoding</varname>
     </fieldsynopsis>
     <fieldsynopsis>
diff --git a/reference/dom/domnode.xml b/reference/dom/domnode.xml
index 402f345797..e426dcf958 100644
--- a/reference/dom/domnode.xml
+++ b/reference/dom/domnode.xml
@@ -53,7 +53,7 @@
     <fieldsynopsis>
      <modifier>public</modifier>
      <modifier>readonly</modifier>
-     <type>DOMNode</type>
+     <type class="union"><type>DOMNode</type><type>null</type></type>
      <varname linkend="domnode.props.parentnode">parentNode</varname>
     </fieldsynopsis>
     <fieldsynopsis>
@@ -65,43 +65,43 @@
     <fieldsynopsis>
      <modifier>public</modifier>
      <modifier>readonly</modifier>
-     <type>DOMNode</type>
+     <type class="union"><type>DOMNode</type><type>null</type></type>
      <varname linkend="domnode.props.firstchild">firstChild</varname>
     </fieldsynopsis>
     <fieldsynopsis>
      <modifier>public</modifier>
      <modifier>readonly</modifier>
-     <type>DOMNode</type>
+     <type class="union"><type>DOMNode</type><type>null</type></type>
      <varname linkend="domnode.props.lastchild">lastChild</varname>
     </fieldsynopsis>
     <fieldsynopsis>
      <modifier>public</modifier>
      <modifier>readonly</modifier>
-     <type>DOMNode</type>
+     <type class="union"><type>DOMNode</type><type>null</type></type>
      <varname linkend="domnode.props.previoussibling">previousSibling</varname>
     </fieldsynopsis>
     <fieldsynopsis>
      <modifier>public</modifier>
      <modifier>readonly</modifier>
-     <type>DOMNode</type>
+     <type class="union"><type>DOMNode</type><type>null</type></type>
      <varname linkend="domnode.props.nextsibling">nextSibling</varname>
     </fieldsynopsis>
     <fieldsynopsis>
      <modifier>public</modifier>
      <modifier>readonly</modifier>
-     <type>DOMNamedNodeMap</type>
+     <type class="union"><type>DOMNamedNodeMap</type><type>null</type></type>
      <varname linkend="domnode.props.attributes">attributes</varname>
     </fieldsynopsis>
     <fieldsynopsis>
      <modifier>public</modifier>
      <modifier>readonly</modifier>
-     <type>DOMDocument</type>
+     <type class="union"><type>DOMDocument</type><type>null</type></type>
      <varname linkend="domnode.props.ownerdocument">ownerDocument</varname>
     </fieldsynopsis>
     <fieldsynopsis>
      <modifier>public</modifier>
      <modifier>readonly</modifier>
-     <type>string</type>
+     <type class="union"><type>string</type><type>null</type></type>
      <varname linkend="domnode.props.namespaceuri">namespaceURI</varname>
     </fieldsynopsis>
     <fieldsynopsis>
@@ -118,7 +118,7 @@
     <fieldsynopsis>
      <modifier>public</modifier>
      <modifier>readonly</modifier>
-     <type>string</type>
+     <type class="union"><type>string</type><type>null</type></type>
      <varname linkend="domnode.props.baseuri">baseURI</varname>
     </fieldsynopsis>
     <fieldsynopsis>