I’m not sure if that’s a perfect example. I know all the things necessary to do the job… I just don’t have time to learn the new things to grow my career. Typically, I set aside about 30~60min exploring the latest technology… but…not any more. Technically, I can do it but there’s a specific threshold of coding I can handle per day. I think my max is 6 hours a day…
Back to your topic, you need to break down the step that you feel comfortable. For example, grab a JavaScript book and see the contents. Make the best guess on what chapter you need to read on. Make the best guess on sample code you find on Google. Lastly, don’t be afraid to just jump right on to it. It’s ok to be completely loss but typically you learn the fastest by actually doing it. It’s like riding a bike… yes you’ll fall a lot but you’ll learn.