This tests the constructors for all the event DOM classes that have them. On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE". PASS (new Event('eventType')).bubbles is false PASS (new Event('eventType')).cancelable is false PASS (new Event('eventType', { bubbles: true, cancelable: true })).bubbles is true PASS (new Event('eventType', { bubbles: true, cancelable: true })).cancelable is true PASS (new Event('eventType', { bubbles: true, cancelable: false })).bubbles is true PASS (new Event('eventType', { bubbles: true, cancelable: false })).cancelable is false PASS (new Event('eventType', { bubbles: true, cancelable: undefined })).bubbles is true PASS (new Event('eventType', { bubbles: true, cancelable: undefined })).cancelable is false PASS (new Event('eventType', { bubbles: true, cancelable: 0 })).bubbles is true PASS (new Event('eventType', { bubbles: true, cancelable: 0 })).cancelable is false PASS (new Event('eventType', { bubbles: true })).bubbles is true PASS (new Event('eventType', { bubbles: true })).cancelable is false PASS (new Event('eventType', { })).bubbles is false PASS (new Event('eventType', { })).cancelable is false PASS (new Event('eventType', null)).bubbles is false PASS (new Event('eventType', null)).cancelable is false PASS (new Event('eventType', undefined)).bubbles is false PASS (new Event('eventType', undefined)).cancelable is false PASS new Event('eventType', 0) threw exception TypeError: Failed to construct 'Event': The provided value is not of type 'EventInit'.. PASS (new Event('eventType', window)).bubbles is false PASS (new Event('eventType', window)).cancelable is false PASS (new Event('eventType', window)).bubbles is true PASS (new Event('eventType', window)).cancelable is false PASS (new Event('eventType', document)).bubbles is true PASS (new Event('eventType', document)).cancelable is false PASS (new Event('eventType', constructible)).bubbles is true PASS (new Event('eventType', constructible)).cancelable is false PASS (new Event('eventType', { bubbles: true, cancelable: true, other: true })).bubbles is true PASS (new Event('eventType', { bubbles: true, cancelable: true, other: true })).cancelable is true PASS (new Event('eventType', { bubbles: true, get cancelable() { return true; } })).bubbles is true PASS (new Event('eventType', { bubbles: true, get cancelable() { return true; } })).cancelable is true PASS (new Event('eventType', { bubbles: true, get cancelable() { return false; } })).bubbles is true PASS (new Event('eventType', { bubbles: true, get cancelable() { return false; } })).cancelable is false PASS new Event('eventType', { bubbles: true, get cancelable() { throw 'Custom Error'; } }) threw exception Custom Error. PASS successfullyParsed is true TEST COMPLETE