diff --git a/karma-tests/wombat.spec.js b/karma-tests/wombat.spec.js
index d735988f..343c295c 100644
--- a/karma-tests/wombat.spec.js
+++ b/karma-tests/wombat.spec.js
@@ -126,6 +126,7 @@ describe('WombatJS', function () {
             initScript: function () {
                 wbinfo = {
                     wombat_opts: {},
+                    wombat_ts: '',
                 };
             },
             wombatScript: wombatScript,
diff --git a/pywb/static/wombat.js b/pywb/static/wombat.js
index 26bcf091..d8656935 100644
--- a/pywb/static/wombat.js
+++ b/pywb/static/wombat.js
@@ -2468,7 +2468,7 @@ var _WBWombat = function($wbwindow, wbinfo) {
 
         wb_abs_prefix = wb_replay_prefix;
 
-        if (!wbinfo.is_live && wbinfo.wombat_ts.length > 0) {
+        if (!wbinfo.is_live && wbinfo.wombat_ts) {
             wb_capture_date_part = "/" + wbinfo.wombat_ts + "/";
         } else {
             wb_capture_date_part = "";