Can we get job by just learning JavaScript?

Answer 1

JavaScript can provide you a job? Yes!
I'd recommend you to go through this article once : https://medium.com/javascript-scene/forget-the-click-bait-here-s-what-the-javascript-job-market-really-looks-like-in-2016-ddfe0d39b467

Answer 2

yes we can. but it's not going to be easy since there are plenty of good developers already out there