diff --git a/mozilla/content/html/content/src/nsHTMLObjectElement.cpp b/mozilla/content/html/content/src/nsHTMLObjectElement.cpp
index 4716137e791..70e12e2f2fc 100644
--- a/mozilla/content/html/content/src/nsHTMLObjectElement.cpp
+++ b/mozilla/content/html/content/src/nsHTMLObjectElement.cpp
@@ -204,6 +204,11 @@ nsHTMLObjectElement::StringToAttribute(nsIAtom* aAttribute,
       return NS_CONTENT_ATTR_HAS_VALUE;
     }
   }
+  else if (aAttribute == nsHTMLAtoms::tabindex) {
+    if (ParseValue(aValue, 0, aResult, eHTMLUnit_Integer)) {
+      return NS_CONTENT_ATTR_HAS_VALUE;
+    }
+  }
   else if (ParseImageAttribute(aAttribute, aValue, aResult)) {
     return NS_CONTENT_ATTR_HAS_VALUE;
   }
diff --git a/mozilla/content/html/content/src/nsHTMLSharedObjectElement.cpp b/mozilla/content/html/content/src/nsHTMLSharedObjectElement.cpp
index 4716137e791..70e12e2f2fc 100644
--- a/mozilla/content/html/content/src/nsHTMLSharedObjectElement.cpp
+++ b/mozilla/content/html/content/src/nsHTMLSharedObjectElement.cpp
@@ -204,6 +204,11 @@ nsHTMLObjectElement::StringToAttribute(nsIAtom* aAttribute,
       return NS_CONTENT_ATTR_HAS_VALUE;
     }
   }
+  else if (aAttribute == nsHTMLAtoms::tabindex) {
+    if (ParseValue(aValue, 0, aResult, eHTMLUnit_Integer)) {
+      return NS_CONTENT_ATTR_HAS_VALUE;
+    }
+  }
   else if (ParseImageAttribute(aAttribute, aValue, aResult)) {
     return NS_CONTENT_ATTR_HAS_VALUE;
   }