diff --git a/dlls/mshtml/editor.c b/dlls/mshtml/editor.c
index 94fa7ace4f4..6fee9c75040 100644
--- a/dlls/mshtml/editor.c
+++ b/dlls/mshtml/editor.c
@@ -333,7 +333,7 @@ static void set_font_size(HTMLDocument *This, LPCWSTR size)
     cpp_bool collapsed;
     nsIDOMHTMLElement *elem;
     nsIDOMRange *range;
-    PRInt32 range_cnt = 0;
+    LONG range_cnt = 0;
     nsAString size_str;
     nsAString val_str;
 
diff --git a/dlls/mshtml/mutation.c b/dlls/mshtml/mutation.c
index a00f81afc3b..aeee77f352c 100644
--- a/dlls/mshtml/mutation.c
+++ b/dlls/mshtml/mutation.c
@@ -525,32 +525,32 @@ static void NSAPI nsDocumentObserver_CharacterDataChanged(nsIDocumentObserver *i
 }
 
 static void NSAPI nsDocumentObserver_AttributeWillChange(nsIDocumentObserver *iface, nsIDocument *aDocument,
-        nsIContent *aContent, PRInt32 aNameSpaceID, nsIAtom *aAttribute, PRInt32 aModType)
+        nsIContent *aContent, LONG aNameSpaceID, nsIAtom *aAttribute, LONG aModType)
 {
 }
 
 static void NSAPI nsDocumentObserver_AttributeChanged(nsIDocumentObserver *iface, nsIDocument *aDocument,
-        nsIContent *aContent, PRInt32 aNameSpaceID, nsIAtom *aAttribute, PRInt32 aModType)
+        nsIContent *aContent, LONG aNameSpaceID, nsIAtom *aAttribute, LONG aModType)
 {
 }
 
 static void NSAPI nsDocumentObserver_AttributeSetToCurrentValue(nsIDocumentObserver *iface, nsIDocument *aDocument,
-        void *aElement, PRInt32 aNameSpaceID, nsIAtom *aAttribute)
+        void *aElement, LONG aNameSpaceID, nsIAtom *aAttribute)
 {
 }
 
 static void NSAPI nsDocumentObserver_ContentAppended(nsIDocumentObserver *iface, nsIDocument *aDocument,
-        nsIContent *aContainer, nsIContent *aFirstNewContent, PRInt32 aNewIndexInContainer)
+        nsIContent *aContainer, nsIContent *aFirstNewContent, LONG aNewIndexInContainer)
 {
 }
 
 static void NSAPI nsDocumentObserver_ContentInserted(nsIDocumentObserver *iface, nsIDocument *aDocument,
-        nsIContent *aContainer, nsIContent *aChild, PRInt32 aIndexInContainer)
+        nsIContent *aContainer, nsIContent *aChild, LONG aIndexInContainer)
 {
 }
 
 static void NSAPI nsDocumentObserver_ContentRemoved(nsIDocumentObserver *iface, nsIDocument *aDocument,
-        nsIContent *aContainer, nsIContent *aChild, PRInt32 aIndexInContainer,
+        nsIContent *aContainer, nsIContent *aChild, LONG aIndexInContainer,
         nsIContent *aProviousSibling)
 {
 }
diff --git a/dlls/mshtml/nsembed.c b/dlls/mshtml/nsembed.c
index fdb11edd072..608684636d6 100644
--- a/dlls/mshtml/nsembed.c
+++ b/dlls/mshtml/nsembed.c
@@ -1333,7 +1333,7 @@ static nsresult NSAPI nsWebBrowserChrome_DestroyBrowserWindow(nsIWebBrowserChrom
 }
 
 static nsresult NSAPI nsWebBrowserChrome_SizeBrowserTo(nsIWebBrowserChrome *iface,
-        PRInt32 aCX, PRInt32 aCY)
+        LONG aCX, LONG aCY)
 {
     NSContainer *This = impl_from_nsIWebBrowserChrome(iface);
     WARN("(%p)->(%d %d)\n", This, aCX, aCY);
@@ -1667,7 +1667,7 @@ static nsrefcnt NSAPI nsEmbeddingSiteWindow_Release(nsIEmbeddingSiteWindow *ifac
 }
 
 static nsresult NSAPI nsEmbeddingSiteWindow_SetDimensions(nsIEmbeddingSiteWindow *iface,
-        PRUint32 flags, PRInt32 x, PRInt32 y, PRInt32 cx, PRInt32 cy)
+        PRUint32 flags, LONG x, LONG y, LONG cx, LONG cy)
 {
     NSContainer *This = impl_from_nsIEmbeddingSiteWindow(iface);
     WARN("(%p)->(%08x %d %d %d %d)\n", This, flags, x, y, cx, cy);
@@ -1675,7 +1675,7 @@ static nsresult NSAPI nsEmbeddingSiteWindow_SetDimensions(nsIEmbeddingSiteWindow
 }
 
 static nsresult NSAPI nsEmbeddingSiteWindow_GetDimensions(nsIEmbeddingSiteWindow *iface,
-        PRUint32 flags, PRInt32 *x, PRInt32 *y, PRInt32 *cx, PRInt32 *cy)
+        PRUint32 flags, LONG *x, LONG *y, LONG *cx, LONG *cy)
 {
     NSContainer *This = impl_from_nsIEmbeddingSiteWindow(iface);
     WARN("(%p)->(%08x %p %p %p %p)\n", This, flags, x, y, cx, cy);
@@ -1778,7 +1778,7 @@ static nsrefcnt NSAPI nsTooltipListener_Release(nsITooltipListener *iface)
 }
 
 static nsresult NSAPI nsTooltipListener_OnShowTooltip(nsITooltipListener *iface,
-        PRInt32 aXCoord, PRInt32 aYCoord, const PRUnichar *aTipText)
+        LONG aXCoord, LONG aYCoord, const PRUnichar *aTipText)
 {
     NSContainer *This = impl_from_nsITooltipListener(iface);
 
diff --git a/dlls/mshtml/nsiface.idl b/dlls/mshtml/nsiface.idl
index ee29c580f4c..13a156b1cce 100644
--- a/dlls/mshtml/nsiface.idl
+++ b/dlls/mshtml/nsiface.idl
@@ -44,7 +44,6 @@ typedef nsIIDRef nsCIDRef;
 
 typedef WCHAR PRUnichar;
 typedef ULONG PRUint32;
-typedef LONG PRInt32;
 typedef WORD PRUint16;
 typedef INT16 PRInt16;
 typedef BYTE PRUint8;
@@ -57,7 +56,7 @@ typedef ULONGLONG PRUint64;
  * use stdint.h types in C.
  */
 #define int16_t PRInt16
-#define int32_t PRInt32
+#define int32_t LONG
 #define int64_t PRInt64
 
 #define uint8_t PRUint8
diff --git a/dlls/mshtml/nsservice.c b/dlls/mshtml/nsservice.c
index 141ece190b1..2eefcbe69bd 100644
--- a/dlls/mshtml/nsservice.c
+++ b/dlls/mshtml/nsservice.c
@@ -126,7 +126,7 @@ static nsresult NSAPI nsPromptService_ConfirmEx(nsIPromptService *iface,
         nsIDOMWindow *aParent, const PRUnichar *aDialogTitle,
         const PRUnichar *aText, PRUint32 aButtonFlags, const PRUnichar *aButton0Title,
         const PRUnichar *aButton1Title, const PRUnichar *aButton2Title,
-        const PRUnichar *aCheckMsg, cpp_bool *aCheckState, PRInt32 *_retval)
+        const PRUnichar *aCheckMsg, cpp_bool *aCheckState, LONG *_retval)
 {
     static const PRUnichar wszContinue[] = {'C','o','n','t','i','n','u','e',0};
 
@@ -186,7 +186,7 @@ static nsresult NSAPI nsPromptService_PromptPassword(nsIPromptService *iface,
 static nsresult NSAPI nsPromptService_Select(nsIPromptService *iface,
         nsIDOMWindow *aParent, const PRUnichar *aDialogTitle,
         const PRUnichar *aText, PRUint32 aCount, const PRUnichar **aSelectList,
-        PRInt32 *aOutSelection, cpp_bool *_retval)
+        LONG *aOutSelection, cpp_bool *_retval)
 {
     FIXME("(%p %s %s %d %p %p %p)\n", aParent, debugstr_w(aDialogTitle),
         debugstr_w(aText), aCount, aSelectList, aOutSelection, _retval);
diff --git a/dlls/mshtml/selection.c b/dlls/mshtml/selection.c
index 9add1e67437..db3b7b32f5c 100644
--- a/dlls/mshtml/selection.c
+++ b/dlls/mshtml/selection.c
@@ -147,7 +147,7 @@ static HRESULT WINAPI HTMLSelectionObject_createRange(IHTMLSelectionObject *ifac
     TRACE("(%p)->(%p)\n", This, range);
 
     if(This->nsselection) {
-        PRInt32 nsrange_cnt = 0;
+        LONG nsrange_cnt = 0;
         nsresult nsres;
 
         nsISelection_GetRangeCount(This->nsselection, &nsrange_cnt);
diff --git a/dlls/mshtml/txtrange.c b/dlls/mshtml/txtrange.c
index 86e9f0b9405..42e49b1610a 100644
--- a/dlls/mshtml/txtrange.c
+++ b/dlls/mshtml/txtrange.c
@@ -392,7 +392,7 @@ static nsIDOMNode *get_child_node(nsIDOMNode *node, PRUint32 off)
 static void get_cur_pos(HTMLTxtRange *This, BOOL start, dompos_t *pos)
 {
     nsIDOMNode *node;
-    PRInt32 off;
+    LONG off;
 
     pos->p = NULL;