Last year, I remember that the JavaScript lecture suddenly became more difficult to listen to from the 8th lecture onwards, but I think they put more effort into the curriculum in the renewal. The learning effect will be higher if you study other things (books, personal projects, etc.) in parallel, but I think this lecture alone is enough to build a solid foundation. In addition, although it is not shown here on Inflearn, there is an HTML/CSS lecture on Zerocho's YouTube, so I recommend that you watch it together. I also recommend purchasing the book. It is not expensive if you think of it as a lecture fee, and it is good for repeated learning.