I just need a bit of help, i am following the video , i am at 25:00, can someone tell me what I am doing wrong?

Have you tried placing a breakpoint on that line? Perhaps you could check what d becomes?
(What happens when you leave the line in?)

Also kindly use const or at least let when defining variables for the current scope in js - it'll make it easier for you when inspecting variables.

Explain what “does not work” means? Is the block not moving in x? Is your computer rebooting?

@Endurion Sorry I did not respond as early as possible, as it was 12:00 am when your post was sent. “does not work” means that in my html file, nothing draws with that specific line, but If i take it out, everything works again

@SuperVGA If i leave the line in, nothing draws

That sounds like there's an exception somewhere. Does something show up in the console?

Nothing shows up in the console, because my school, for some reason, blocked the inspect element . SO theres no way for me to see the console.

Are you able to upload the broken state somewhere accessible? So maybe others can take a peek. Since that's plain javaScript it's probably string multiplied by number or some other error that would not happen with any decent language.

@Endurion to be clear, you want me to send the drive link for you guys to open in your text editor?

Ideally something so we can run the site in our browser. Not all browsers are locked down.