diff --git a/content/base/public/nsIContentSerializer.h b/content/base/public/nsIContentSerializer.h
index 6731ece4f9c..367c0ba94b1 100644
--- a/content/base/public/nsIContentSerializer.h
+++ b/content/base/public/nsIContentSerializer.h
@@ -52,8 +52,8 @@ class nsAString;
 /* starting interface:    nsIContentSerializer */
 
 #define NS_ICONTENTSERIALIZER_IID \
-{ 0x0921afbc, 0x4c6f, 0x4249, \
-  { 0xa7, 0xf5, 0x32, 0xe4, 0x91, 0xbf, 0x6e, 0x32 } }
+{ 0x34769de0, 0x30d0, 0x4cef, \
+  { 0x89, 0x4a, 0xfc, 0xd8, 0xbb, 0x27, 0xc4, 0xb4 } }
 
 class nsIContentSerializer : public nsISupports {
  public: 
@@ -61,7 +61,8 @@ class nsIContentSerializer : public nsISupports {
   NS_DECLARE_STATIC_IID_ACCESSOR(NS_ICONTENTSERIALIZER_IID)
 
   NS_IMETHOD Init(PRUint32 flags, PRUint32 aWrapColumn,
-                  const char* aCharSet, PRBool aIsCopying) = 0;
+                  const char* aCharSet, PRBool aIsCopying,
+                  PRBool aIsWholeDocument) = 0;
 
   NS_IMETHOD AppendText(nsIDOMText* aText, PRInt32 aStartOffset,
                         PRInt32 aEndOffset, nsAString& aStr) = 0;
diff --git a/content/base/src/mozSanitizingSerializer.cpp b/content/base/src/mozSanitizingSerializer.cpp
index 53359478541..74eece9a397 100644
--- a/content/base/src/mozSanitizingSerializer.cpp
+++ b/content/base/src/mozSanitizingSerializer.cpp
@@ -126,7 +126,8 @@ NS_IMPL_ISUPPORTS4(mozSanitizingHTMLSerializer,
 
 NS_IMETHODIMP 
 mozSanitizingHTMLSerializer::Init(PRUint32 aFlags, PRUint32 dummy,
-                                  const char* aCharSet, PRBool aIsCopying)
+                                  const char* aCharSet, PRBool aIsCopying,
+                                  PRBool aIsWholeDocument)
 {
   NS_ENSURE_TRUE(nsContentUtils::GetParserService(), NS_ERROR_UNEXPECTED);
 
@@ -138,7 +139,7 @@ mozSanitizingHTMLSerializer::Initialize(nsAString* aOutString,
                                         PRUint32 aFlags,
                                         const nsAString& allowedTags)
 {
-  nsresult rv = Init(aFlags, 0, nsnull, PR_FALSE);
+  nsresult rv = Init(aFlags, 0, nsnull, PR_FALSE, PR_FALSE);
   NS_ENSURE_SUCCESS(rv, rv);
 
   // XXX This is wrong. It violates XPCOM string ownership rules.
diff --git a/content/base/src/mozSanitizingSerializer.h b/content/base/src/mozSanitizingSerializer.h
index ca15f415c00..6b3473eb6f9 100644
--- a/content/base/src/mozSanitizingSerializer.h
+++ b/content/base/src/mozSanitizingSerializer.h
@@ -72,7 +72,7 @@ public:
 
   // nsIContentSerializer
   NS_IMETHOD Init(PRUint32 flags, PRUint32 dummy, const char* aCharSet, 
-                  PRBool aIsCopying);
+                  PRBool aIsCopying, PRBool aIsWholeDocument);
 
   NS_IMETHOD AppendText(nsIDOMText* aText, PRInt32 aStartOffset,
                         PRInt32 aEndOffset, nsAString& aStr);
diff --git a/content/base/src/nsDocumentEncoder.cpp b/content/base/src/nsDocumentEncoder.cpp
index 120f7a1263b..43ea060e106 100644
--- a/content/base/src/nsDocumentEncoder.cpp
+++ b/content/base/src/nsDocumentEncoder.cpp
@@ -893,7 +893,9 @@ nsDocumentEncoder::EncodeToString(nsAString& aOutputString)
       NS_ENSURE_SUCCESS(rv, rv);
     }
   }
-  mSerializer->Init(mFlags, mWrapColumn, mCharset.get(), mIsCopying);
+  
+  PRBool isWholeDocument = !(mSelection || mRange || mNode);
+  mSerializer->Init(mFlags, mWrapColumn, mCharset.get(), mIsCopying, isWholeDocument);
 
   if (mSelection) {
     nsCOMPtr<nsIDOMRange> range;
diff --git a/content/base/src/nsHTMLContentSerializer.cpp b/content/base/src/nsHTMLContentSerializer.cpp
index 0eae3d73886..8ec31220fe5 100644
--- a/content/base/src/nsHTMLContentSerializer.cpp
+++ b/content/base/src/nsHTMLContentSerializer.cpp
@@ -93,6 +93,7 @@ nsHTMLContentSerializer::nsHTMLContentSerializer()
   mInBody(PR_FALSE),
   mAddSpace(PR_FALSE),
   mMayIgnoreLineBreakSequence(PR_FALSE),
+  mIsWholeDocument(PR_FALSE),
   mInCDATA(PR_FALSE),
   mNeedLineBreaker(PR_TRUE)
 {
@@ -112,7 +113,8 @@ nsHTMLContentSerializer::~nsHTMLContentSerializer()
 
 NS_IMETHODIMP 
 nsHTMLContentSerializer::Init(PRUint32 aFlags, PRUint32 aWrapColumn,
-                              const char* aCharSet, PRBool aIsCopying)
+                              const char* aCharSet, PRBool aIsCopying,
+                              PRBool aIsWholeDocument)
 {
   mFlags = aFlags;
   if (!aWrapColumn) {
@@ -122,6 +124,7 @@ nsHTMLContentSerializer::Init(PRUint32 aFlags, PRUint32 aWrapColumn,
     mMaxColumn = aWrapColumn;
   }
 
+  mIsWholeDocument = aIsWholeDocument;
   mIsCopying = aIsCopying;
   mIsFirstChildOfOL = PR_FALSE;
   mDoFormat = (mFlags & nsIDocumentEncoder::OutputFormatted) ? PR_TRUE
@@ -636,7 +639,7 @@ nsHTMLContentSerializer::AppendElementStart(nsIDOMElement *aElement,
 
   // We need too skip any meta tags that set the content type
   // becase we set our own later.
-  if (name == nsGkAtoms::meta) {
+  if (mIsWholeDocument && name == nsGkAtoms::meta) {
     nsAutoString header;
     content->GetAttr(kNameSpaceID_None, nsGkAtoms::httpEquiv, header);
     if (header.LowerCaseEqualsLiteral("content-type")) {
@@ -738,7 +741,7 @@ nsHTMLContentSerializer::AppendElementStart(nsIDOMElement *aElement,
     mInCDATA = PR_TRUE;
   }
 
-  if (name == nsGkAtoms::head) {
+  if (mIsWholeDocument && name == nsGkAtoms::head) {
     AppendToString(mLineBreak, aStr);
     AppendToString(NS_LITERAL_STRING("<meta http-equiv=\"content-type\""),
                    aStr);
@@ -765,7 +768,7 @@ nsHTMLContentSerializer::AppendElementEnd(nsIDOMElement *aElement,
   nsIAtom *name = content->Tag();
 
   // So that we don't mess up the line breaks.
-  if (name == nsGkAtoms::meta) {
+  if (mIsWholeDocument && name == nsGkAtoms::meta) {
     nsAutoString header;
     content->GetAttr(kNameSpaceID_None, nsGkAtoms::httpEquiv, header);
     if (header.LowerCaseEqualsLiteral("content-type")) {
diff --git a/content/base/src/nsHTMLContentSerializer.h b/content/base/src/nsHTMLContentSerializer.h
index 94c9d2c256a..8cf89f2e880 100644
--- a/content/base/src/nsHTMLContentSerializer.h
+++ b/content/base/src/nsHTMLContentSerializer.h
@@ -58,7 +58,8 @@ class nsHTMLContentSerializer : public nsXMLContentSerializer {
   virtual ~nsHTMLContentSerializer();
 
   NS_IMETHOD Init(PRUint32 flags, PRUint32 aWrapColumn,
-                  const char* aCharSet, PRBool aIsCopying);
+                  const char* aCharSet, PRBool aIsCopying,
+                  PRBool aIsWholeDocument);
 
   NS_IMETHOD AppendText(nsIDOMText* aText, 
                         PRInt32 aStartOffset,
@@ -139,6 +140,10 @@ class nsHTMLContentSerializer : public nsXMLContentSerializer {
   PRPackedBool  mAddSpace;
   PRPackedBool  mMayIgnoreLineBreakSequence;
 
+  // This is to ensure that we only do meta tag fixups when dealing with
+  // whole documents.
+  PRPackedBool  mIsWholeDocument;
+
   // To keep track of First LI child of OL in selected range 
   PRPackedBool  mIsFirstChildOfOL;
   PRInt32       mPreLevel;
diff --git a/content/base/src/nsPlainTextSerializer.cpp b/content/base/src/nsPlainTextSerializer.cpp
index ff512b5e27e..ef3146520a7 100644
--- a/content/base/src/nsPlainTextSerializer.cpp
+++ b/content/base/src/nsPlainTextSerializer.cpp
@@ -149,7 +149,8 @@ NS_IMPL_ISUPPORTS4(nsPlainTextSerializer,
 
 NS_IMETHODIMP 
 nsPlainTextSerializer::Init(PRUint32 aFlags, PRUint32 aWrapColumn,
-                            const char* aCharSet, PRBool aIsCopying)
+                            const char* aCharSet, PRBool aIsCopying,
+                            PRBool aIsWholeDocument)
 {
 #ifdef DEBUG
   // Check if the major control flags are set correctly.
@@ -274,7 +275,7 @@ NS_IMETHODIMP
 nsPlainTextSerializer::Initialize(nsAString* aOutString,
                                   PRUint32 aFlags, PRUint32 aWrapCol)
 {
-  nsresult rv = Init(aFlags, aWrapCol, nsnull, PR_FALSE);
+  nsresult rv = Init(aFlags, aWrapCol, nsnull, PR_FALSE, PR_FALSE);
   NS_ENSURE_SUCCESS(rv, rv);
 
   // XXX This is wrong. It violates XPCOM string ownership rules.
diff --git a/content/base/src/nsPlainTextSerializer.h b/content/base/src/nsPlainTextSerializer.h
index c46f267404a..cccf5a3ff6e 100644
--- a/content/base/src/nsPlainTextSerializer.h
+++ b/content/base/src/nsPlainTextSerializer.h
@@ -69,7 +69,8 @@ public:
 
   // nsIContentSerializer
   NS_IMETHOD Init(PRUint32 flags, PRUint32 aWrapColumn,
-                  const char* aCharSet, PRBool aIsCopying);
+                  const char* aCharSet, PRBool aIsCopying,
+                  PRBool aIsWholeDocument);
 
   NS_IMETHOD AppendText(nsIDOMText* aText, PRInt32 aStartOffset,
                         PRInt32 aEndOffset, nsAString& aStr);
diff --git a/content/base/src/nsXMLContentSerializer.cpp b/content/base/src/nsXMLContentSerializer.cpp
index 20e10fa7c16..19a04757a89 100644
--- a/content/base/src/nsXMLContentSerializer.cpp
+++ b/content/base/src/nsXMLContentSerializer.cpp
@@ -93,7 +93,8 @@ NS_IMPL_ISUPPORTS1(nsXMLContentSerializer, nsIContentSerializer)
 
 NS_IMETHODIMP 
 nsXMLContentSerializer::Init(PRUint32 flags, PRUint32 aWrapColumn,
-                             const char* aCharSet, PRBool aIsCopying)
+                             const char* aCharSet, PRBool aIsCopying,
+                             PRBool aIsWholeDocument)
 {
   mCharset = aCharSet;
   return NS_OK;
diff --git a/content/base/src/nsXMLContentSerializer.h b/content/base/src/nsXMLContentSerializer.h
index 556eb578d76..e0ae47988af 100644
--- a/content/base/src/nsXMLContentSerializer.h
+++ b/content/base/src/nsXMLContentSerializer.h
@@ -60,7 +60,8 @@ class nsXMLContentSerializer : public nsIContentSerializer {
   NS_DECL_ISUPPORTS
 
   NS_IMETHOD Init(PRUint32 flags, PRUint32 aWrapColumn,
-                  const char* aCharSet, PRBool aIsCopying);
+                  const char* aCharSet, PRBool aIsCopying,
+                  PRBool aIsWholeDocument);
 
   NS_IMETHOD AppendText(nsIDOMText* aText, PRInt32 aStartOffset,
                         PRInt32 aEndOffset, nsAString& aStr);
diff --git a/content/base/test/Makefile.in b/content/base/test/Makefile.in
index dcbd8d909b0..fa56b4dcf9a 100644
--- a/content/base/test/Makefile.in
+++ b/content/base/test/Makefile.in
@@ -86,6 +86,7 @@ _TEST_FILES = 	test_bug5141.html \
 		test_bug373181.xhtml \
 		test_bug375314.html \
 		test_bug382113.html \
+		test_bug390735.html \
 		bug382113_object.html \
 		test_CrossSiteXHR.html \
 		file_CrossSiteXHR_fail1.xml \
diff --git a/content/base/test/test_bug390735.html b/content/base/test/test_bug390735.html
new file mode 100644
index 00000000000..92248c9a06b
--- /dev/null
+++ b/content/base/test/test_bug390735.html
@@ -0,0 +1,29 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=390735
+-->
+<head>
+  <meta http-equiv="content-type" content="text/html; charset=utf-8">
+  <title>Test for Bug 390735</title>
+  <script type="text/javascript" src="/MochiKit/MochiKit.js"></script>
+  <script type="text/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>        
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
+</head>
+<body>
+<p id="display"></p>
+<div id="content" style="display: none">
+  
+</div>
+<pre id="test">
+<script class="testbody" type="text/javascript">
+/** Test for Bug 390735 **/
+
+var contents = document.getElementsByTagName("head")[0].innerHTML;
+var expectedFind = "<meta http-equiv=\"content-type\" content=\"text/html; charset=utf-8\">";
+
+ok(contents.indexOf(expectedFind) > -1, "The meta tag element was not found");
+</script>
+</pre>
+</body>
+</html>