If we're talking about JS/PHP, we're talking about web development. Front-end stuff has to be done in JS (you can use something else that compiles to JS but I e

If we're talking about JS/PHP, we're talking about web development. Front-end stuff has to be done in JS (you can use something else that compiles to JS but I expect you would find that difficult with zero JS knowledge). Back-end stuff can be done in any language, although some (e.g. PHP, Ruby, Python, JS) are more common than say C++. So you can do web development using only JS. But different languages have different pros/cons/approaches, so it's definitely worth venturing outside the JS world at some point. However, if you're still relatively new to JS you should focus on getting to a decent level in that first.