- it's /highly/ accessible (any computer with a browser can compile and run javascript - you just need to get your browser to load the file)
- it shares a lot of its syntax with C-Style languages (which makes transference to other languages much easier
- it's 'relaxed' on how it enforces rules (now, this is contentious, should a learner be allowed to get away with mistakes that will haunt them later, or should a learner be hobbled and forced to be precise from the get-go, IMO the former is easier for people to upskil with than the latter)
- it's (currently) got commercial value (that is, you can get a job with javascript on your CV)