stripe.card.validateCardNumber not working

[LabN36]

I've tried below all possible statement for validateCardNumber but none of them working please guide me what I'm doing wrong

1.    console.log(stripe.card.validateCardNumber('4242424242424242'));
2.    stripe.card.validateCardNumber('4242424242424242',function(res){
        console.log(res);
    });
3.    stripe.card.validateCardNumber('4242424242424242').then(function (res) {
        console.log(res);
    });