diff --git a/source/Ox/js/Format.js b/source/Ox/js/Format.js
index b04fb507..52f21d1b 100644
--- a/source/Ox/js/Format.js
+++ b/source/Ox/js/Format.js
@@ -682,7 +682,7 @@ Ox.formatISBN = function(isbn, length, dashes) {
         ret.slice(-9, -6),
         ret.slice(-6, -1),
         ret.slice(-1)
-    ].join('-').replace(/^-/, '') : ret;
+    ].join('-').replace(/^-+/, '') : ret;
 };
 
 /*@