Question

function foo() {
    bar = 'ok';
    new baz( this );
}

function baz( foo ) {
    alert( foo.bar );
}

new foo();

Why is it that the alert shows “undefined” instead of “ok”?

Answer 1

bar has gone out of scope. There is a difference between scope and context. if you want to attach a property to foo, you must attach the property to the function.

function foo() {
     this.bar = 'ok';
     new baz(this);
    }

function baz(foo) {
    alert(foo.bar);
    }

new foo();​