Platform Support
| IE | Mozilla | Netscape | Opera | Safari | 3.0+ | 1.0+ | 3.0+ | 7.0+ | 1.0+ |
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Constructors
| Constructor | Action | IE | Mozilla | Netscape | Opera | Safari | |||||
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Boolean Constructor(Boolean value) : Boolean
Creates a new instance of a Boolean object.
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Show Details | 3.0+ | 1.0+ | 3.0+ | 7.0+ | 1.0+ | |||||
Boolean(Boolean value) : BooleanCreates a new instance of a Boolean object. Parameters
Returns
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Properties
| Property | Action | IE | Mozilla | Netscape | Opera | Safari |
|---|---|---|---|---|---|---|
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constructor
: Object
Specifies the function that creates the Boolean prototype.
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Show Details | 4.0+ | 1.0+ | 3.0+ | 7.0+ | 1.0+ |
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prototype
: Object
Represents the Boolean prototype object.
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Show Details | 4.0+ | 1.0+ | 3.0+ | 7.0+ | 1.0+ |
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Functions
| Method | Action | IE | Mozilla | Netscape | Opera | Safari | ||
|---|---|---|---|---|---|---|---|---|
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toSource() : String
Returns a string representing the source code of a Boolean object.
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Show Details | 4.0+ | 1.0+ | 4.0+ | no | no | ||
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Returns
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toString() : String
Returns a string representing the specified Boolean
object.
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Show Details | 4.0+ | 1.0+ | 3.0+ | 7.0+ | 1.0+ | ||
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Returns
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valueOf() : Boolean
Returns the primitive value of a Boolean object.
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Show Details | 4.0+ | 1.0+ | 3.0+ | 7.0+ | 1.0+ | ||
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Returns
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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 trueThis 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 falseDo 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 useIf 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 trueDo not use a Boolean object in place of a Boolean primitive.
References
Availability
JavaScript 1.1|JScript 2.0|ECMAScript v1
