When you are applying for the position of a project manager, you at least need to know the difference between PHP and JavaScript. However, in my case, I was unaware of it, so I had to learn a lot, day after day.
I must say that it is a quite common practice in the IT industry that PM is from the “outside world”. So, I am not the first and, of course, not the last one, and if you ask me how actually it is working, the answer will be “differently”.