javascript var vs this [duplicate]

Answer 1

If you want to use properties once you instantiate the object, var won't work, see below:

function MyObject() {
    var self = this;

    var a = 1;
    this.b = 2;

    var innerMethod = function() {

        logMessage(a); 
        logMessage(self.b); 
    }
}

var o = new MyObject();
console.log(o.a); // undefined
console.log(o.b); // 2