jQuery date picker not working for anonymous user in expose form

Uncaught ReferenceError: Drupal is not defined at better_exposed_filters.js:34 bef_datepickers.js:29 Uncaught ReferenceError: Drupal is not defined at bef_datepickers.js:29. these two errors are shown on the browser console .I am using better expose filter to display the authored date in expose form ...

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