This is going to sound really, really basic, but I just need a little help understanding one of the concepts I'm struggling with in Javascript. I have been reading tutorials on loops, if/elseif/else and so on, I have a fairly decent understanding of them and how they work, but it's implementing and using them I am really confused about.

Just to be clear, I understand how to link my script.js file to my index.html. What I am having trouble understanding is how the Javascript I write, is influenced and connected to the HTML/CSS I write.

For example, if building a quiz, if I write a Submit button in HTML, how do I link my Javascript to that button, how does my Javascript know what I want to do with that button, and how does that button (submitting an answer > calculating how many correct answers I have submitted) connect to the rest of my Javascript input (listing questions, calculating how many correct answers I have, submitting them)?

Is there a particular name for the topic that covers this and will help me learn to understand it?