The Boolean object is an object wrapper for a Boolean value and is constructed with the above Boolean constructor. If there is no initial value or it is 0, -0, null, false, NaN, undefined or the empty string (""), the initial value is false. Otherwise, even with the string "false", it is true. So, all the following objects have an initial value of false:

x = new Boolean()
x = new Boolean(0)
x = new Boolean(-0)
x = new Boolean(null)
x = new Boolean(false)
x = new Boolean(NaN)
x = new Boolean(undefined)
x = new Boolean("")

...whereas in the following examples the Boolean object 'x' has an initial value of true:

myBool = new Boolean(false)
x = new Boolean(myBool)

x = new Boolean("false")

Any Boolean object that is passed to a conditional statement (except those with an initial value of null or undefined) evaluates to true. So, for instance, the conditional statement in the following code evaluates to true.

Code:
x = new Boolean(false)
if(x)

However, this does not apply to Boolean primitives, and the conditional statement in the following code evaluates to false.

Code:
x = false
if(x)

NOTE:

In JavaScript 1.3 and later versions, don't use a Boolean object instead of a Boolean primitive, nor should you use a Boolean object to convert a non-Boolean value to a Boolean one. To do so use Boolean as a function. For example, the following converts the expression 'a+b' to a Boolean value:

Code:
x = Boolean(a+b)

PROPERTIES

constructor property
This property specifies the function that created the object's prototype. See also the Object.constructor property.

Syntax: object.constructor

prototype property
This property represents the prototype for this object and allows you to add methods and properties of your own. See also the Function.prototype property.

Syntax: object.prototype

METHODS

toSource method
This method, which is usually called internally by JavaScript, returns a string representing the source code of the object. It overrides the Object.toSource method.

Syntax: object.toSource()

toString method
This method converts a Boolean object to a string representing its value: i.e. either "true" or "false", and is called by JavaScript automatically whenever a Boolean object is used in a situation requiring a string. This method overrides the Object.toString method.

Syntax: object.toString()

valueOf method
This method, which is usually called internally by JavaScript, returns a primitive value (either "true" or "false") for the Boolean object. It overrides the Object.valueOf method.

Syntax: object.valueOf()

NOTE:

The Boolean object also inherits the watch and unwatch methods from the Object object.