Javascript-全局范围或本地范围，无法弄清楚

Question

I am not able to figure it out if d is a global variable or because of (,) it will have a local scope like abc?

I think a , b and c have local scope and d is having a local scope.

function something(param) {
    var a, b, c= {
            someNumber: 7,
            someObject: {},
        },
        d= {}
}

Answer 1

d是局部的，因为逗号将其保留在var语句中。

Answer 2

You can theorize all you want, but nothing beats solving it walking :

function something(param) {
    var a, b, c= {
            someNumber: 7,
            someObject: {},
        },
        d= {}
}

something()
console.log(d);

produces:

ReferenceError: d is not defined