diff --git a/editor/libeditor/html/nsWSRunObject.cpp b/editor/libeditor/html/nsWSRunObject.cpp
index 6e7c7fad44e..dc22490e5cd 100644
--- a/editor/libeditor/html/nsWSRunObject.cpp
+++ b/editor/libeditor/html/nsWSRunObject.cpp
@@ -733,7 +733,7 @@ nsWSRunObject::GetWSNodes()
       for (pos=mOffset-1; pos>=0; pos--)
       {
         // sanity bounds check the char position.  bug 136165
-        if (pos >= textFrag->GetLength())
+        if (PRUint32(pos) >= textFrag->GetLength())
         {
           NS_NOTREACHED("looking beyond end of text fragment");
           continue;
@@ -801,7 +801,7 @@ nsWSRunObject::GetWSNodes()
           for (pos=len-1; pos>=0; pos--)
           {
             // sanity bounds check the char position.  bug 136165
-            if (pos >= textFrag->GetLength())
+            if (PRUint32(pos) >= textFrag->GetLength())
             {
               NS_NOTREACHED("looking beyond end of text fragment");
               continue;
@@ -860,13 +860,13 @@ nsWSRunObject::GetWSNodes()
     const nsTextFragment *textFrag = textNode->GetText();
 
     PRUint32 len = textNode->TextLength();
-    if (mOffset<len)
+    if (PRUint16(mOffset)<len)
     {
       PRInt32 pos;
-      for (pos=mOffset; pos<len; pos++)
+      for (pos=mOffset; PRUint32(pos)<len; pos++)
       {
         // sanity bounds check the char position.  bug 136165
-        if ((pos<0) || (pos>=textFrag->GetLength()))
+        if ((pos<0) || (PRUint32(pos)>=textFrag->GetLength()))
         {
           NS_NOTREACHED("looking beyond end of text fragment");
           continue;
@@ -932,10 +932,10 @@ nsWSRunObject::GetWSNodes()
         else
         {
           PRInt32 pos;
-          for (pos=0; pos<len; pos++)
+          for (pos=0; PRUint32(pos)<len; pos++)
           {
             // sanity bounds check the char position.  bug 136165
-            if (pos >= textFrag->GetLength())
+            if (PRUint32(pos) >= textFrag->GetLength())
             {
               NS_NOTREACHED("looking beyond end of text fragment");
               continue;
@@ -1587,7 +1587,7 @@ nsWSRunObject::DeleteChars(nsIDOMNode *aStartNode, PRInt32 aStartOffset,
       textnode = do_QueryInterface(node);
       PRUint32 len;
       textnode->GetLength(&len);
-      if (aStartOffset<len)
+      if (PRUint32(aStartOffset)<len)
       {
         res = mHTMLEditor->DeleteText(textnode, (PRUint32)aStartOffset, len-aStartOffset);
         NS_ENSURE_SUCCESS(res, res);
@@ -1695,7 +1695,7 @@ nsWSRunObject::GetCharAfter(WSPoint &aPoint, WSPoint *outPoint)
   if (idx == -1) return NS_OK;  // can't find point, but it's not an error
   PRInt32 numNodes = mNodeArray.Count();
   
-  if (aPoint.mOffset < aPoint.mTextNode->TextLength())
+  if (PRUint16(aPoint.mOffset) < aPoint.mTextNode->TextLength())
   {
     *outPoint = aPoint;
     outPoint->mChar = GetCharAt(aPoint.mTextNode, aPoint.mOffset);
@@ -1941,7 +1941,7 @@ nsWSRunObject::GetCharAt(nsIContent *aTextNode, PRInt32 aOffset)
     return 0;
 
   PRUint32 len = aTextNode->TextLength();
-  if (aOffset < 0 || aOffset >= len) 
+  if (aOffset < 0 || aOffset >= PRUint32(len)) 
     return 0;
     
   return aTextNode->GetText()->CharAt(aOffset);
diff --git a/editor/libeditor/text/nsTextEditRules.cpp b/editor/libeditor/text/nsTextEditRules.cpp
index 4c7673c92ae..02ff60b7fbe 100644
--- a/editor/libeditor/text/nsTextEditRules.cpp
+++ b/editor/libeditor/text/nsTextEditRules.cpp
@@ -534,8 +534,8 @@ GetTextNode(nsISelection *selection, nsEditor *editor) {
 #define ASSERT_PASSWORD_LENGTHS_EQUAL()                                \
   if (IsPasswordEditor()) {                                            \
     PRInt32 txtLen;                                                    \
-    mEditor->GetTextLength(&txtLen);                                   \
-    NS_ASSERTION(mPasswordText.Length() == txtLen,                     \
+    mEditor->GetTextLength(&txtLen);                                    \
+    NS_ASSERTION(mPasswordText.Length() == PRUint32(txtLen),           \
                  "password length not equal to number of asterisks");  \
   }
 #else
diff --git a/editor/txtsvc/src/nsTextServicesDocument.cpp b/editor/txtsvc/src/nsTextServicesDocument.cpp
index 885c13ed9a2..2c86da8c050 100644
--- a/editor/txtsvc/src/nsTextServicesDocument.cpp
+++ b/editor/txtsvc/src/nsTextServicesDocument.cpp
@@ -4028,8 +4028,9 @@ nsTextServicesDocument::FindWordBounds(nsTArray<OffsetEntry*> *aOffsetTable,
     // character covered by this entry, we will use the next
     // entry if there is one.
 
-    if (entry->mStrOffset <= res.mBegin &&
-       (res.mBegin < strEndOffset || (res.mBegin == strEndOffset && i == lastIndex)))
+    if (PRUint32(entry->mStrOffset) <= res.mBegin &&
+        (res.mBegin < PRUint32(strEndOffset) ||
+        (res.mBegin == PRUint32(strEndOffset) && i == lastIndex)))
     {
       if (aWordStartNode)
       {
@@ -4052,9 +4053,9 @@ nsTextServicesDocument::FindWordBounds(nsTArray<OffsetEntry*> *aOffsetTable,
     // Check to see if res.mEnd is within the range covered
     // by this entry.
 
-    if (entry->mStrOffset <= res.mEnd && res.mEnd <= strEndOffset)
+    if (PRUint32(entry->mStrOffset) <= res.mEnd && res.mEnd <= PRUint32(strEndOffset))
     {
-      if (res.mBegin == res.mEnd && res.mEnd == strEndOffset && i != lastIndex)
+      if (res.mBegin == res.mEnd && res.mEnd == PRUint32(strEndOffset) && i != lastIndex)
       {
         // Wait for the next round so that we use the same entry
         // we did for aWordStartNode.