diff --git a/addons/web/static/src/js/data_import.js b/addons/web/static/src/js/data_import.js
index 079239c357e..c65112afe5f 100644
--- a/addons/web/static/src/js/data_import.js
+++ b/addons/web/static/src/js/data_import.js
@@ -18,7 +18,7 @@ function jsonp(form, attributes, callback) {
     attributes = attributes || {};
     var options = {jsonp: _.uniqueId('import_callback_')};
     window[options.jsonp] = function () {
-        delete window[options.jsonp];
+        window[options.jsonp] = null;
         callback.apply(null, arguments);
     };
     if ('data' in attributes) {