What happens with “var” variables inside a JavaScript Constructor?

Question

example:

function Foo() {
    this.bla = 1;
    var blabla = 10;
    blablabla = 100;
    this.getBlabla = function () { 
        return blabla; // exposes b         


        

Answer 1

blabla can almost be considered a private member of Foo.

See this article from Douglas Crockford.