diff --git a/content/html/content/src/nsHTMLInputElement.cpp b/content/html/content/src/nsHTMLInputElement.cpp
index 41e1a03709c4..b39b8496fdec 100644
--- a/content/html/content/src/nsHTMLInputElement.cpp
+++ b/content/html/content/src/nsHTMLInputElement.cpp
@@ -907,6 +907,8 @@ nsHTMLInputElement::AfterSetAttr(PRInt32 aNameSpaceID, nsIAtom* aName,
       UpdateTooLongValidityState();
     } else if (aName == nsGkAtoms::pattern) {
       UpdatePatternMismatchValidityState();
+    } else if (aName == nsGkAtoms::multiple) {
+      UpdateTypeMismatchValidityState();
     }
 
     UpdateEditableState(aNotify);