diff --git a/dev/js/src/vc/doc.js b/dev/js/src/vc/doc.js
index 2d38b56..821aa64 100644
--- a/dev/js/src/vc/doc.js
+++ b/dev/js/src/vc/doc.js
@@ -112,6 +112,7 @@
       }
       else {
         this._valueE.addT(loc.EMPTY);
+        this._valueE.classList.add('unspecified');
       };
 
       // Change value