When I run following html,css,js it is running but not running in sololearn?

Question

https://code.sololearn.com/Wr0BtkqyvnKE/?ref=app

Answer 1

Gajjala Venkata Sai Sri Harsha Hanumantha Rao , the whole code in the JS should be inside window. onload. Look at the code.
https://code.sololearn.com/Wf7s1xiP36bj/?ref=app

Answer 2

TheWh¡teCat 🇧🇬 thanks for helping. May I know reason why should we write that in sololearn but even if I did not write in my code editor it runs.

Answer 3

Different browsers and different app versions have different loading orders. window.onload() explicitly loads the script as the window loads