How do I save some user's data in my JS or HTML files? Is it even possible or I need a database language?
— Depends what data
— Is it private?
— An example: the user will have to type in a fruit name and the fruit's calories. I want it to be saved in my file, so when someone else calls that same fruit it should show the calories added by the previous user
— So is there a way to save the added fruit & calories in my JS array & object?
— What do you mean with "save"? temporarily? permanently? From the front-end alone you cannot "save" files or to db. But you can request an API to do it for you. So the backend needs to take care of that. There are also serverless services, that allow you to write stuff without needing to host a backend