Boolean

Syntax:: new Boolean(value)

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.

Examples

Code:

x = new Boolean("false") 

          if(x)

Explanation:

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 this code evaluates to true.

Code:

x = false 

          if(x)

Explanation:

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

Code:

x = Boolean(a+b)

Explanation:

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. This example converts the expression 'a+b' to a Boolean value.

Code:

  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("")

Explanation:

All of these objects have an initial value of false.

Code:

myBool = new Boolean(false) 

          x = new Boolean(myBool)

x = new Boolean("false")

Explanation:

In these examples the Boolean object 'x' has an initial value of true

Properties

constructor

Syntax: Object.constructor

This specifies a function to create an object's property and is inherited by all objects from their prototype.

prototype

Syntax: Object.prototype.name = value

This allows the addition of properties and methods to any object.

Methods

eval

Syntax: Object.eval(string)

The eval method is deprecated as a method of Object, but is still used as a high level function. It evaluates a string of JavaScript in the context of an object.

toSource

Syntax: Object.toSource()

The toSource method returns a literal representing the source code of an object. This can then be used to create a new object.

toString