toString(16) with leading zeroes

When you convert a small number to a hexadecimal representation, you need leading zeroes, because `toString(16)` will return `f` for `15`, instead of `00000f`. Usually I will use the loop like this: ``` var s = X.toString(16); while (s.length < 6) s = '0' + s ``` is there a better way in JavaScript? UPD: The answer suggested answer How can I create a Zerofilled value using JavaScript? is not what I am looking for, I look for a very short code, that is suited specifically for 24 bit integers converted to a hexadecimal looking strings.