Front-end (Frontend) developers are responsible for the entire development cycle of the front-end (the one that we see) of the site or application (for example SPA). Fronted is based on three components. HTML, CSS, JavaScript. If everything is clear and simple with the first two, then JavaScript opens up a huge "world" for the developer with a bunch of frameworks like Angular, React, Vue and others. Javascript is one of the most in-demand skills in web development today, we recommend that you carefully read it before starting to learn frameworks.