I was following the teacher's activity in my workspace and none of them worked for me like in the video.Version?
1. const box = document.querySelector(".box"); box.style.display = "none";
The box disappeared in about a second later
The box remained there. No change on the site.
Steven Parker186,980 Points
When you say "about a second later", do you mean a second after you refreshed your browser?
The workspace provide a way to create code for your browser, but changes made there will not be visible on their own. You can only see the results of code changes by first saving the file and then refreshing your browser.
For #2 it just looks like you didn't close the single quotes around the box class. A simple typo that we all make.