Casting to Boolean value : Type Conversion « Number Data Type « JavaScript Tutorial

1. JavaScript Tutorial
2. Number Data Type
3. Type Conversion

The Boolean() type cast returns true when

the value is a string with at least one character,

a number other than 0, or

an object;

The Boolean() type cast returns false when

1. the value is an empty string,
2. the number 0,
3. undefined, or
4. null.

var b1 = Boolean("");              //false -- empty string
var b2 = Boolean("JavaScript");    //true -- non-empty string
var b3 = Boolean(100);             //true -- non-zero number
var b4 = Boolean(null);            //false -- null
var b5 = Boolean(0);               //false -- zero
var b6 = Boolean(new Object());    //true -- object