i wonder why this very simple solution doesn't get nearly as much "best practice" than the other one above there >^.^<

What else you want me to do?

Damn, balu9 has no chill (⊙_⊙;)

Nice

Nice!

What unexpected behaviour are you talking about here? The ECMA specification says that the radix will default to 10 unless the string starts with "0x", which can't happen here as all non-numeric characters are removed.

If radix is undefined or 0, it is assumed to be 10 except when the number begins with the code unit pairs 0x or 0X, in which case a radix of 16 is assumed. If radix is 16, the number may also optionally begin with the code unit pairs 0x or 0X.

https://262.ecma-international.org/12.0/#sec-parseint-string-radix

I am, I look for it!

Of course, as long as you are ok with your code having unexpected behavior :D

I should do what I fancy to.

You should always provide radix (10 in this case) as the second argument to parseInt.

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/parseInt

As far as I know, not using var will put any declaration in the global scope. So while you wouldn't want to do that on a real production app. Using it for these little solutions isn't necessarily wrong. As you probably don't need to worry about your namespace

here's an example:
drink = 'beer'
function drunk () {
console.log(drink)
}
drunk()
//'beer'
function wino () {
var drink = 'wine';
console.log(drink)
}
wino()
// 'wine'
drink
// 'beer'

why var is not used in this solution?