[jrs95]

It's now the most popular programming language by a decent margin, there are a lot of libraries available for it, and it lacks some of the performance limitations that affect other dynamic languages. Anyone that does frontend dev knows JavaScript, its about as close to a universal language as you can get.

Personally theres about a dozen other things I'd rather use but from a pragmatic perspective it makes sense. It's easy and it gets the job done relatively quickly.