Why can't I see anything in OKAH when I start the application?

Question

PHP

Good afternoon! I'm a beginner, I wanted to create my own game in the windows, those that are, I'm tired of it. Life simulator, I did everything right, like, added an application, almost filled all the fields, but when I go to the application itself, a blank screen is displayed. What could it be?! Why won't the app open? It is necessary to install something additional in the browser. Thanks to all who responded.

Answer 1

What is worth working on?

learn to write beautiful, neat code.
Now this is shitty code. And the most important task of a programmer is to write code that is understandable, first of all, to a HUMAN.
Open any popular open source framework and see how elegant each code file is.

Answer 2

to separate data from its representation i.e. create a view, this is how you see it yourself and it bothers you.