How to test a browser game?

Question

Software testing

Good day to all) I would like to understand how you can test a browser game. Is it necessary to have access to the server side or can it be done like a parser and see what the browser itself returns? What sources can be read, Google does not particularly provide information on testing browsers. And what libraries and PL are more often used for tests? I know C# a little, I thought to write tests based on it. It is not clear what is better to use for the web part + sharp. Take Asp.net or something....