diff --git a/mozilla/layout/forms/nsComboboxControlFrame.cpp b/mozilla/layout/forms/nsComboboxControlFrame.cpp
index b1dcccc145c..23d46131712 100644
--- a/mozilla/layout/forms/nsComboboxControlFrame.cpp
+++ b/mozilla/layout/forms/nsComboboxControlFrame.cpp
@@ -337,7 +337,9 @@ PRBool
 nsComboboxControlFrame::IsSuccessful(nsIFormControlFrame* aSubmitter)
 {
   nsAutoString name;
-  return (NS_CONTENT_ATTR_HAS_VALUE == GetName(&name));
+  PRBool disabled = PR_FALSE;
+  nsFormControlHelper::GetDisabled(mContent, &disabled);
+  return !disabled && (NS_CONTENT_ATTR_HAS_VALUE == GetName(&name));
 }
 
 // If nothing is selected, and we have options, select item 0
diff --git a/mozilla/layout/forms/nsFileControlFrame.cpp b/mozilla/layout/forms/nsFileControlFrame.cpp
index 862a428160b..6c38339b622 100644
--- a/mozilla/layout/forms/nsFileControlFrame.cpp
+++ b/mozilla/layout/forms/nsFileControlFrame.cpp
@@ -181,7 +181,9 @@ PRBool
 nsFileControlFrame::IsSuccessful(nsIFormControlFrame* aSubmitter)
 {
   nsAutoString name;
-  return (NS_CONTENT_ATTR_HAS_VALUE == GetName(&name));
+  PRBool disabled = PR_FALSE;
+  nsFormControlHelper::GetDisabled(mContent, &disabled);
+  return !disabled && (NS_CONTENT_ATTR_HAS_VALUE == GetName(&name));
 }
 
 void 
diff --git a/mozilla/layout/forms/nsFormControlFrame.cpp b/mozilla/layout/forms/nsFormControlFrame.cpp
index 67077c83435..8dcd42c9ad0 100644
--- a/mozilla/layout/forms/nsFormControlFrame.cpp
+++ b/mozilla/layout/forms/nsFormControlFrame.cpp
@@ -762,10 +762,14 @@ PRBool
 nsFormControlFrame::IsSuccessful(nsIFormControlFrame* aSubmitter)
 {
   nsAutoString name;
+  PRBool disabled = PR_FALSE;
+  nsFormControlHelper::GetDisabled(mContent, &disabled);
+
   // Since JS Submit() calls are not linked to an element, aSubmitter is null.
   // Return success to allow the call to go through.
   if (aSubmitter == nsnull) return PR_TRUE;
-  return (NS_CONTENT_ATTR_HAS_VALUE == GetName(&name));
+
+  return !disabled && (NS_CONTENT_ATTR_HAS_VALUE == GetName(&name));
 }
 
 NS_METHOD
diff --git a/mozilla/layout/forms/nsFormControlHelper.cpp b/mozilla/layout/forms/nsFormControlHelper.cpp
index 5b3b4a44e6d..bf94eab0cf4 100644
--- a/mozilla/layout/forms/nsFormControlHelper.cpp
+++ b/mozilla/layout/forms/nsFormControlHelper.cpp
@@ -1399,3 +1399,21 @@ nsFormControlHelper::GetLocalizedString(char* aKey, nsString& oVal)
   return rv;
 }
 
+// Return value of disabled attribute or PR_FALSE if none set
+nsresult
+nsFormControlHelper::GetDisabled(nsIContent* aContent, PRBool* oIsDisabled)
+{
+  nsCOMPtr<nsIHTMLContent> formControl = do_QueryInterface(aContent);
+  nsHTMLValue value;
+  nsresult result = formControl->GetHTMLAttribute(nsHTMLAtoms::disabled, value);
+  if (NS_CONTENT_ATTR_HAS_VALUE == result) {
+    if (eHTMLUnit_Empty == value.GetUnit()) {
+      *oIsDisabled = PR_TRUE;
+    } else {
+      *oIsDisabled = PR_FALSE;
+    }
+  } else {
+    *oIsDisabled = PR_FALSE;
+  }
+  return NS_OK;
+}
diff --git a/mozilla/layout/forms/nsFormControlHelper.h b/mozilla/layout/forms/nsFormControlHelper.h
index 840548fb740..8ea3b7c08c5 100644
--- a/mozilla/layout/forms/nsFormControlHelper.h
+++ b/mozilla/layout/forms/nsFormControlHelper.h
@@ -179,6 +179,8 @@ public:
 
   // Localization Helper
   static nsresult GetLocalizedString(char* aKey, nsString& oVal);
+
+  static nsresult GetDisabled(nsIContent* aContent, PRBool* oIsDisabled);
 //
 //-------------------------------------------------------------------------------------
 //  Utility methods for managing checkboxes and radiobuttons
diff --git a/mozilla/layout/forms/nsGfxButtonControlFrame.cpp b/mozilla/layout/forms/nsGfxButtonControlFrame.cpp
index 148fc40767e..605b40eb6af 100644
--- a/mozilla/layout/forms/nsGfxButtonControlFrame.cpp
+++ b/mozilla/layout/forms/nsGfxButtonControlFrame.cpp
@@ -41,14 +41,18 @@ nsGfxButtonControlFrame::IsSuccessful(nsIFormControlFrame* aSubmitter)
 {
   PRInt32 type;
   GetType(&type);
+  PRBool successful = PR_TRUE;
   if ((NS_FORM_INPUT_HIDDEN == type) || (this == aSubmitter)) {
      // Can not use the nsHTMLButtonControlFrame::IsSuccessful because
      // it will fail it's test of (this==aSubmitter)
     nsAutoString name;
-    return (NS_CONTENT_ATTR_HAS_VALUE == GetName(&name));
+    PRBool disabled = PR_FALSE;
+    nsFormControlHelper::GetDisabled(mContent, &disabled);
+    successful = !disabled && (NS_CONTENT_ATTR_HAS_VALUE == GetName(&name));
   } else {
-    return PR_FALSE;
+    successful = PR_FALSE;
   }
+  return successful;
 }
 
 PRInt32
diff --git a/mozilla/layout/forms/nsHTMLButtonControlFrame.cpp b/mozilla/layout/forms/nsHTMLButtonControlFrame.cpp
index 8e22916aad8..59f955b13cc 100644
--- a/mozilla/layout/forms/nsHTMLButtonControlFrame.cpp
+++ b/mozilla/layout/forms/nsHTMLButtonControlFrame.cpp
@@ -280,12 +280,16 @@ nsHTMLButtonControlFrame::GetValue(nsString* aResult)
 PRBool
 nsHTMLButtonControlFrame::IsSuccessful(nsIFormControlFrame* aSubmitter)
 {
+  PRBool successful = PR_TRUE;
   if (this == (aSubmitter)) {
     nsAutoString name;
-    return (NS_CONTENT_ATTR_HAS_VALUE == GetName(&name));
+    PRBool disabled = PR_FALSE;
+    nsFormControlHelper::GetDisabled(mContent, &disabled);
+    successful = !disabled && (NS_CONTENT_ATTR_HAS_VALUE == GetName(&name));
   } else {
-    return PR_FALSE;
+    successful = PR_FALSE;
   }
+  return successful;
 }
 
 PRBool
diff --git a/mozilla/layout/forms/nsListControlFrame.cpp b/mozilla/layout/forms/nsListControlFrame.cpp
index 52726c1f189..bd6c193224a 100644
--- a/mozilla/layout/forms/nsListControlFrame.cpp
+++ b/mozilla/layout/forms/nsListControlFrame.cpp
@@ -1738,7 +1738,9 @@ PRBool
 nsListControlFrame::IsSuccessful(nsIFormControlFrame* aSubmitter)
 {
   nsAutoString name;
-  return (NS_CONTENT_ATTR_HAS_VALUE == GetName(&name));
+  PRBool disabled = PR_FALSE;
+  nsFormControlHelper::GetDisabled(mContent, &disabled);
+  return !disabled && (NS_CONTENT_ATTR_HAS_VALUE == GetName(&name));
 }
 
 
diff --git a/mozilla/layout/html/forms/src/nsComboboxControlFrame.cpp b/mozilla/layout/html/forms/src/nsComboboxControlFrame.cpp
index b1dcccc145c..23d46131712 100644
--- a/mozilla/layout/html/forms/src/nsComboboxControlFrame.cpp
+++ b/mozilla/layout/html/forms/src/nsComboboxControlFrame.cpp
@@ -337,7 +337,9 @@ PRBool
 nsComboboxControlFrame::IsSuccessful(nsIFormControlFrame* aSubmitter)
 {
   nsAutoString name;
-  return (NS_CONTENT_ATTR_HAS_VALUE == GetName(&name));
+  PRBool disabled = PR_FALSE;
+  nsFormControlHelper::GetDisabled(mContent, &disabled);
+  return !disabled && (NS_CONTENT_ATTR_HAS_VALUE == GetName(&name));
 }
 
 // If nothing is selected, and we have options, select item 0
diff --git a/mozilla/layout/html/forms/src/nsFileControlFrame.cpp b/mozilla/layout/html/forms/src/nsFileControlFrame.cpp
index 862a428160b..6c38339b622 100644
--- a/mozilla/layout/html/forms/src/nsFileControlFrame.cpp
+++ b/mozilla/layout/html/forms/src/nsFileControlFrame.cpp
@@ -181,7 +181,9 @@ PRBool
 nsFileControlFrame::IsSuccessful(nsIFormControlFrame* aSubmitter)
 {
   nsAutoString name;
-  return (NS_CONTENT_ATTR_HAS_VALUE == GetName(&name));
+  PRBool disabled = PR_FALSE;
+  nsFormControlHelper::GetDisabled(mContent, &disabled);
+  return !disabled && (NS_CONTENT_ATTR_HAS_VALUE == GetName(&name));
 }
 
 void 
diff --git a/mozilla/layout/html/forms/src/nsFormControlFrame.cpp b/mozilla/layout/html/forms/src/nsFormControlFrame.cpp
index 67077c83435..8dcd42c9ad0 100644
--- a/mozilla/layout/html/forms/src/nsFormControlFrame.cpp
+++ b/mozilla/layout/html/forms/src/nsFormControlFrame.cpp
@@ -762,10 +762,14 @@ PRBool
 nsFormControlFrame::IsSuccessful(nsIFormControlFrame* aSubmitter)
 {
   nsAutoString name;
+  PRBool disabled = PR_FALSE;
+  nsFormControlHelper::GetDisabled(mContent, &disabled);
+
   // Since JS Submit() calls are not linked to an element, aSubmitter is null.
   // Return success to allow the call to go through.
   if (aSubmitter == nsnull) return PR_TRUE;
-  return (NS_CONTENT_ATTR_HAS_VALUE == GetName(&name));
+
+  return !disabled && (NS_CONTENT_ATTR_HAS_VALUE == GetName(&name));
 }
 
 NS_METHOD
diff --git a/mozilla/layout/html/forms/src/nsFormControlHelper.cpp b/mozilla/layout/html/forms/src/nsFormControlHelper.cpp
index 5b3b4a44e6d..bf94eab0cf4 100644
--- a/mozilla/layout/html/forms/src/nsFormControlHelper.cpp
+++ b/mozilla/layout/html/forms/src/nsFormControlHelper.cpp
@@ -1399,3 +1399,21 @@ nsFormControlHelper::GetLocalizedString(char* aKey, nsString& oVal)
   return rv;
 }
 
+// Return value of disabled attribute or PR_FALSE if none set
+nsresult
+nsFormControlHelper::GetDisabled(nsIContent* aContent, PRBool* oIsDisabled)
+{
+  nsCOMPtr<nsIHTMLContent> formControl = do_QueryInterface(aContent);
+  nsHTMLValue value;
+  nsresult result = formControl->GetHTMLAttribute(nsHTMLAtoms::disabled, value);
+  if (NS_CONTENT_ATTR_HAS_VALUE == result) {
+    if (eHTMLUnit_Empty == value.GetUnit()) {
+      *oIsDisabled = PR_TRUE;
+    } else {
+      *oIsDisabled = PR_FALSE;
+    }
+  } else {
+    *oIsDisabled = PR_FALSE;
+  }
+  return NS_OK;
+}
diff --git a/mozilla/layout/html/forms/src/nsFormControlHelper.h b/mozilla/layout/html/forms/src/nsFormControlHelper.h
index 840548fb740..8ea3b7c08c5 100644
--- a/mozilla/layout/html/forms/src/nsFormControlHelper.h
+++ b/mozilla/layout/html/forms/src/nsFormControlHelper.h
@@ -179,6 +179,8 @@ public:
 
   // Localization Helper
   static nsresult GetLocalizedString(char* aKey, nsString& oVal);
+
+  static nsresult GetDisabled(nsIContent* aContent, PRBool* oIsDisabled);
 //
 //-------------------------------------------------------------------------------------
 //  Utility methods for managing checkboxes and radiobuttons
diff --git a/mozilla/layout/html/forms/src/nsGfxButtonControlFrame.cpp b/mozilla/layout/html/forms/src/nsGfxButtonControlFrame.cpp
index 148fc40767e..605b40eb6af 100644
--- a/mozilla/layout/html/forms/src/nsGfxButtonControlFrame.cpp
+++ b/mozilla/layout/html/forms/src/nsGfxButtonControlFrame.cpp
@@ -41,14 +41,18 @@ nsGfxButtonControlFrame::IsSuccessful(nsIFormControlFrame* aSubmitter)
 {
   PRInt32 type;
   GetType(&type);
+  PRBool successful = PR_TRUE;
   if ((NS_FORM_INPUT_HIDDEN == type) || (this == aSubmitter)) {
      // Can not use the nsHTMLButtonControlFrame::IsSuccessful because
      // it will fail it's test of (this==aSubmitter)
     nsAutoString name;
-    return (NS_CONTENT_ATTR_HAS_VALUE == GetName(&name));
+    PRBool disabled = PR_FALSE;
+    nsFormControlHelper::GetDisabled(mContent, &disabled);
+    successful = !disabled && (NS_CONTENT_ATTR_HAS_VALUE == GetName(&name));
   } else {
-    return PR_FALSE;
+    successful = PR_FALSE;
   }
+  return successful;
 }
 
 PRInt32
diff --git a/mozilla/layout/html/forms/src/nsGfxTextControlFrame2.cpp b/mozilla/layout/html/forms/src/nsGfxTextControlFrame2.cpp
index ce8718b5dc9..5bfad207873 100644
--- a/mozilla/layout/html/forms/src/nsGfxTextControlFrame2.cpp
+++ b/mozilla/layout/html/forms/src/nsGfxTextControlFrame2.cpp
@@ -2085,7 +2085,9 @@ PRBool
 nsGfxTextControlFrame2::IsSuccessful(nsIFormControlFrame* aSubmitter)
 {
   nsAutoString name;
-  return (NS_CONTENT_ATTR_HAS_VALUE == GetName(&name));
+  PRBool disabled = PR_FALSE;
+  nsFormControlHelper::GetDisabled(mContent, &disabled);
+  return !disabled && (NS_CONTENT_ATTR_HAS_VALUE == GetName(&name));
 }
 
 NS_IMETHODIMP 
diff --git a/mozilla/layout/html/forms/src/nsHTMLButtonControlFrame.cpp b/mozilla/layout/html/forms/src/nsHTMLButtonControlFrame.cpp
index 8e22916aad8..59f955b13cc 100644
--- a/mozilla/layout/html/forms/src/nsHTMLButtonControlFrame.cpp
+++ b/mozilla/layout/html/forms/src/nsHTMLButtonControlFrame.cpp
@@ -280,12 +280,16 @@ nsHTMLButtonControlFrame::GetValue(nsString* aResult)
 PRBool
 nsHTMLButtonControlFrame::IsSuccessful(nsIFormControlFrame* aSubmitter)
 {
+  PRBool successful = PR_TRUE;
   if (this == (aSubmitter)) {
     nsAutoString name;
-    return (NS_CONTENT_ATTR_HAS_VALUE == GetName(&name));
+    PRBool disabled = PR_FALSE;
+    nsFormControlHelper::GetDisabled(mContent, &disabled);
+    successful = !disabled && (NS_CONTENT_ATTR_HAS_VALUE == GetName(&name));
   } else {
-    return PR_FALSE;
+    successful = PR_FALSE;
   }
+  return successful;
 }
 
 PRBool
diff --git a/mozilla/layout/html/forms/src/nsListControlFrame.cpp b/mozilla/layout/html/forms/src/nsListControlFrame.cpp
index 52726c1f189..bd6c193224a 100644
--- a/mozilla/layout/html/forms/src/nsListControlFrame.cpp
+++ b/mozilla/layout/html/forms/src/nsListControlFrame.cpp
@@ -1738,7 +1738,9 @@ PRBool
 nsListControlFrame::IsSuccessful(nsIFormControlFrame* aSubmitter)
 {
   nsAutoString name;
-  return (NS_CONTENT_ATTR_HAS_VALUE == GetName(&name));
+  PRBool disabled = PR_FALSE;
+  nsFormControlHelper::GetDisabled(mContent, &disabled);
+  return !disabled && (NS_CONTENT_ATTR_HAS_VALUE == GetName(&name));
 }