var verbIds = {
    initialized: 'https://w3id.org/xapi/adb/verbs/initialized',
    progressed: 'http://adlnet.gov/expapi/verbs/progressed',
    completed: 'http://adlnet.gov/expapi/verbs/completed',
    accessed: 'https://w3id.org/xapi/seriousgames/verbs/accessed',