How to add a loading part to a webpage

Question

How do you make it so the page says loading until all the elements are loaded then it shows the elements.

An example of what I mean is this how it says loading:
https://code.sololearn.com/WGObAy7i6amA/#js

Answer 1

I think for that you need to know JavaScript.....until the script is loaded it says loading and u could add progress bar etc......

Answer 2

Not really what I’m asking @Striker

Answer 3

add progress....i think u knw about it ....?dont u ?