JavaScript: fields or properties

Some browser vendor have implemented getters/setters for JavaScript properties.

FF and Webkit has __defineGetter__and __defineSetter__ implemented for DOM objects and get and set for Object's which is outside of the ECMA specification. However both and also IE 8+ has the Object.defineProperty (from the ECMA specification). Read about it here

As for you original question, I would say that the reason it's called property in JavaScript is that it's a dynamic language and the basic markup uses only properties and local var's. Since everything is bound to a specific scope-hierarchy all you have is different tree-branches on each level. And Douglas Croockford named them properties :)