A JavaScript developer does work with front-end web developer and is responsible for the client-side interface and he should make sure that the website is responsive, interactive, and user-friendly. A JavaScript developer must also communicate with back-end developers. Whereas, a full-stack JavaScript developer must take care of both the front as well as the back-end of the web applications or websites to make a smooth user-experience possible.
On this note, I would suggest you take a look at the Web Development courses from Intellipaat which is taught at industry-standards to help you gain proficiency along with guided projects to enhance your hands-on experience. These courses come with Lifetime 24*7 technical support.
Also, do check out our YouTube video on JavaScript Developer from our experts to help you get started.