title: How to connect backend and frontend
body: <p>I am very new to frontend programming so please bare with me. In school we learned backend programming languages such as Java, C#, Python, C and some C++. As a hobby I have by myself tried to learn frontend so I started with Vue, JavaScript, HTML and CSS. In school we usually run our code in terminal (for backend programming), for example we did a bubblesort algorithm and then we provide some user input (via terminal) and then call bubblesort to sort the input. The thing is when I write a program in backend and I want to make a website to it, how can I connect my backend to my frontend? Lets take a simple webpge as an example where I write a program that sorts my numbers with bubblesort and then I want to be able to make the user write an array in a website and then click ”sort” button. When he/she clicks it, my backend bubblesort function should be called and so on. I have searched on google but all I can find is other websites providing services to make websites, I want to program from scratch both backend and frontend and connect them together. Is there a way? If yes, does every language has its own way or is there a common way? What I mean is maybe I write backend with Java for one website but another website I write it with Python. Is there a difference in how to connect back and frontend then?
  Thanks in advance.</p>