It's a web browser, so it has to run JavaScript. A browser that doesn't run JavaScript is like a car with no wheels - it doesn't work. (JavaScript is the programming language running in a web browser - any web browser - because that's what the site sends the browser.)
It may or may not use cookies, you'd have to ask the developer. If you can use it with a "remember me" function on a site, so you don't have to log in after the first time, it's using cookies (that's how the function is done).