Underscore prefix for property and method names in JavaScript

Question

Is the underscore prefix in JavaScript only a convention, like for example in Python private class methods are?

From the 2.7 Python documentation:

Answer 1

JSDoc 3 allows you to annotate your functions with the @access private (previously the @private tag) which is also useful for broadcasting your intent to other developers - http://usejsdoc.org/tags-access.html