The actual functionality is built into the web browser so that the desired actions can take place.
As soon as you install those things onto your page, you have this programming language as a part of your site.
Either way, this gives you full control over what you want your website to do and how you want your visitors to interact with the page.
From there, you can code in some additional functionality that enlarges an image when the user puts their mouse over a picture. This lets you create a unique page with very little custom coding on your end.
What Should You Do Next?
This programming language is surprisingly easy to learn. Whether you already know how to code in other languages, or this would be your first one, you can start learning this language right away.