diff --git a/lib/documentListeners.js b/lib/documentListeners.js
index f798e3522..a2b6aa68b 100644
--- a/lib/documentListeners.js
+++ b/lib/documentListeners.js
@@ -20,7 +20,11 @@ function inputIsNumberValue(input) {
   return (type === 'number' || (type === 'range' && !input.multiple));
 }
 function inputValue(input) {
-  return inputIsNumberValue(input) ? input.valueAsNumber : input.value;
+  if (!inputIsNumberValue(input))
+    return input.value;
+  else
+    return (isFinite(input.valueAsNumber)) ?
+      input.valueAsNumber : '';
 }
 
 function addDocumentListeners(doc) {