Platform Support
| IE | Mozilla | Netscape | Opera | Safari |
|---|---|---|---|---|
| 3.0+ | 1.0+ | 3.0+ | 7.0+ | 1.0+ |
Constructors
| Constructor | Action | IE | Mozilla | Netscape | Opera | Safari |
|---|---|---|---|---|---|---|
|
Boolean Constructor(Boolean value) : Boolean
Creates a new instance of a Boolean object.
|
Show Details | 3.0+ | 1.0+ | 3.0+ | 7.0+ | 1.0+ |
Properties
| Property | Action | IE | Mozilla | Netscape | Opera | Safari |
|---|---|---|---|---|---|---|
|
constructor : Object
Specifies the function that creates the Boolean prototype.
|
Show Details | 4.0+ | 1.0+ | 3.0+ | 7.0+ | 1.0+ |
|
prototype : Object
Represents the Boolean prototype object.
|
Show Details | 4.0+ | 1.0+ | 3.0+ | 7.0+ | 1.0+ |
Functions
| Method | Action | IE | Mozilla | Netscape | Opera | Safari |
|---|---|---|---|---|---|---|
|
toSource() : String
Returns a string representing the source code of a Boolean object.
|
Show Details | 4.0+ | 1.0+ | 4.0+ | no | no |
|
toString() : String
Returns a string representing the specified Boolean object.
|
Show Details | 4.0+ | 1.0+ | 3.0+ | 7.0+ | 1.0+ |
|
valueOf() : Boolean
Returns the primitive value of a Boolean object.
|
Show Details | 4.0+ | 1.0+ | 3.0+ | 7.0+ | 1.0+ |
Creating 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);
Creating 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");
Remarks
Do not confuse the primitive Boolean values true and false with the true and false values of the Boolean object.
Any object whose value is not undefined or null, including a Boolean object whose value is false, evaluates to true when
passed to a conditional statement. For example, the condition in the following
if statement evaluates to true:
x = new Boolean(false);
if (x) //the condition is true
This behavior does not apply to Boolean primitives. For example, the condition
in the following if statement evaluates to false:
x = false;
if (x) //the condition is false
Do not use a Boolean object to convert a non-boolean value to a boolean value. Instead, use
Boolean as a function to perform this task:
x = Boolean(expression); //preferred
x = new Boolean(expression); //don't use
If you specify any object, including a Boolean object whose value is false, as the initial value of a Boolean object, the new Boolean object has a value of true.
myFalse = new Boolean(false); // initial value of false
g = new Boolean(myFalse); //initial value of true
myString = new String("Hello"); // string object
s = new Boolean(myString); //initial value of true
Do not use a Boolean object in place of a Boolean primitive.
References
Availability
JavaScript 1.1|JScript 2.0|ECMAScript v1