1 files changed, 1 insertions, 1 deletions
diff --git a/lib/js/urweb.js b/lib/js/urweb.js
index 4435bffa..56066d26 100644
--- a/lib/js/urweb.js
+++ b/lib/js/urweb.js
@@ -1104,7 +1104,7 @@ function sspn(s, chs) {
         if (chs.indexOf(s.charAt(i)) != -1)
             return i;
 
-    return null;
+    return s.length;
 }
 function schr(s, ch) {
     var r = s.indexOf(ch);