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Boolean

The Boolean object is an object wrapper for a boolean value.

Core object

Implemented in

Navigator 3.0, LiveWire 1.0

Created by

The Boolean constructor:

new Boolean(value)

Parameters

value
The initial value of the Boolean object. The value is converted to a boolean value, if necessary. If value is omitted or is 0, null, false, or the empty string (""), the object has an initial value of false. All other values, including the string "false", create an object with an initial value of true.

Description

Use a Boolean object when you need to convert a non-boolean value to a boolean value. You can use the Boolean object any place JavaScript expects a primitive boolean value. JavaScript returns the primitive value of the Boolean object by automatically invoking the valueOf method.

Property Summary

prototype
Defines a property that is shared by all Boolean objects.

Method Summary

toString
Returns a string representing the specified object.

Examples

The following examples create Boolean objects with an initial value of false:

bNoParam = new Boolean()
bZero = new Boolean(0)
bNull = new Boolean(null)
bEmptyString = new Boolean("")
bfalse = new Boolean(false)
The following examples create Boolean objects with an initial value of true:

btrue = new Boolean(true)
btrueString = new Boolean("true")
bfalseString = new Boolean("false")
bSuLin = new Boolean("Su Lin")

Properties

prototype

Represents the prototype for this class. You can use the prototype to add properties or methods to all instances of a class. For information on prototypes, see Function.prototype.

Property of

Boolean

Implemented in

Navigator 3.0, LiveWire 1.0

Methods

toString

Returns a string representing the specified object.

Method of

Boolean

Implemented in

Navigator 3.0, LiveWire 1.0

Syntax

toString()

Parameters

None.

Description

Every object has a toString method that is automatically called when it is to be represented as a text value or when an object is referred to in a string concatenation.

You can use toString within your own code to convert an object into a string, and you can create your own function to be called in place of the default toString method.

For Boolean objects and values, the built-in toString method returns "true" or "false" depending on the value of the boolean object. In the following code, flag.toString returns "true".

flag = new Boolean(true)
document.write("flag.toString() is " + flag.toString() + "<BR>")
For information on defining your own toString method, see the Object.toString method.


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Last Updated: 10/31/97 16:00:33


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