Any Help on why the function doesn't work

Question

If i press the button the rect does not show

https://code.sololearn.com/WXD6d6IT5BF8/?ref=app

Answer 1

Because draw function is not global. It is local to that anonymous function you assigned to window.onload.
Put that code in a script tag in html part(remove window.onload) or Use addEventListener.

Answer 2

Here you go , i fixed it ☺
https://code.sololearn.com/Wu4yCDP3hvEp/?ref=app

Answer 3

Fixed it

https://code.sololearn.com/W2QNAzW5m430/?ref=app

Answer 4

Thanks for the help