Pls whats wrong with this code its working perfectly on my acode app but is not working here why pls guys need help

Question

https://code.sololearn.com/W2a3SYKBoiQP/?ref=app

Answer 1

In this case, javascript is loaded before the html document and therefore does not see the html elements it is referring to.
Use the onload method:
onload = function(){your code}

Answer 2

Thanks its working perfectly