Do you want to use document.write()? It doesn't work.

Please use console.log() ;-)

I'm using JS and get that:

Time: 265ms Passed: 2 Failed: 0 Errors: 1
Test Results:
✔ Test Passed: Value == 0
✔ Test Passed: Value == 0
ReferenceError: document is not defined
at duplicateCount

What does it mean?