What does it mean when there is a number parameter passed to toString?

Question

I'm just wondering what it means to attach a number as a parameter to the toString() method

E.g. obj.toString(10);

I googled and i have never seen a parameter before.

Answer 1

The additional parameter works only for Number.prototype.toString to specify the radix (integer between 2 and 36 specifying the base to use for representing numeric values):

var number = 12345; number.toString(2) === "11000000111001" number.toString(3) === "121221020" // … number.toString(36) === "9ix" 

Answer 2

This only works on Number objects and is intended to give you a way of displaying a number with a certain radix:

var n = 256; var d = n.toString(10); // decimal: "256" var o = n.toString(8);  // octal:   "400" var h = n.toString(16); // hex:     "100" var b = n.toString(2);  // binary:  "100000000" var w = n.toString(20); // base 20: "cg" 

Note that the radix must be an integer between 2 and 36 or toString() will raise an error.