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The Boolean object is an object wrapper for a boolean value.
Boolean
Created by
The Boolean constructor:
new Boolean( value );
Parameters
| Parameter | Description |
|---|---|
| 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, -0, null, false, NaN, undefined, or the empty string (""), the object has an initial value of false. All other values, including any object or the string "false", create an object with an initial value of true. |
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:
This behavior does not apply to Boolean primitives. For example, the condition in the following if statement evaluates to 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.
Returns an object literal representing the specified Boolean object; you can use this value to create a new object. Overrides the Object.toSource method. | |
Returns a string representing the specified object. Overrides the Object.toString method. | |
Returns the primitive value of a Boolean object. Overrides the Object.valueOf method. |
In addition, this object inherits the Object.watch and Object.unwatch methods from Object.
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" );
