JSON/RESTful

http://www.w3schools.com/json/
http://betterexplained.com/articles/using-json-to-exchange-data/

http://www.restapitutorial.com/

JSON and RESTful services aren't necessarily intertwined but often used together.

JSON is essentialy a standard of putting together a chunk of data, it might contain data of any sort, it just must be put as
{ "tag" : "value", "tag2": [ {"subtag1":"value"},{"subtag2":"value"}]}

RESTful however is a standard of accessing service and data objects with addressing based on the URI instead of passing a bunch of parameters, and desired action specified by HTTP GET,POST,PUT,DELETE requests.

It might be well shown in a comparison vs. usual way of passing parameters into php:
domain.com/userservice.php?person=John&action=delete

RESTful api would rather expect HTTP DELETE request sent to

domain.com/userservice/John

hope this is clear enough for you.

Neither of them are a part of JavaScript per se, but both are extensively used by most of JS-based frameworks (like AngularJS), REST is a common standard reaching much beyond any specific programming language. If you want to have a piece of good practice, I would recommend searching for the MEAN Machine book and following the tutorial. Also CodeSchool has a few courses teaching hese topics by example (building a simple site with AngularJS will make you learn  both JSON and REST)

I dont see the course "building a simple site with AngularJS"

As well,  I have 15 years of experience in VB6/VBA/VBS  with some MSSQL, and 2 year experience of PHP/MySQL. Would that be sufficient prerequisite for success in learning RESTful, or must I know Java?

tex exact name is "Shaping up with Angular.js"

no, you don't have to learn Java. If you are familiar with fundamental programming concepts and understand principles of SOA-like architecture (Service oriented) and/or microservices, REST is just another way to implement that and is language independent as it's essentially a concept, not the specific technology.

What's SOA? Is my experience sufficient

Thank you for all your information and sorry for abandoning this.   I got distracted with other issues, but if I have further questions I will open a new question.