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 if 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)

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.