The this keyword is found in various programming languages, and behaves a certain way in JavaScript. Apparently even experienced developers get confused by it.
See this codepen for some example code. It showcases one of the six ways this is used in JavaScript - thanks to what I learned from Zell Liew's great blog post. I really recommend this post for beginners - you can try the examples in your console! In short, this can be used globally, in object constructions, object methods, simple functions, arrow functions, and event listeners. See the MDN docs for more code-heavy examples.