1 files changed, 1 insertions, 1 deletions
diff --git a/src/Browser.js b/src/Browser.js
index 3299540c..3287cf0e 100644
--- a/src/Browser.js
+++ b/src/Browser.js
@@ -67,7 +67,7 @@ Browser.prototype = {
       script.src = url.replace('JSON_CALLBACK', callbackId);
       this.head.append(script);
       window[callbackId] = function(data){
-        delete window[callbackId];
+        window[callbackId] = undefined;
         callback(200, data);
       };
     } else {