Boolean |
support for boolean values |
Availability
JavaScript 1.1; JScript 2.0; ECMAScript
v1
Inherits from/Overrides
Inherits from Object
Constructor
new Boolean(value) //Constructor function
Boolean(value) // Conversion function
Arguments
- value
-
The value to be held by the Boolean object or to be converted to a
boolean value.
Returns
When invoked as a constructor with the new
operator, Boolean( ) converts its argument to a
boolean value and returns a Boolean object that contains that value.
When invoked as a function, without the new
operator, Boolean( ) simply converts its argument
to a primitive boolean value and returns that value.
The values 0, NaN, null, the empty string
"", and the undefined value are
all converted to false. All other primitive
values, except false (but including the string
"false"), and all objects and arrays are converted to
true.
Methods
- toString( )
-
Returns true or false,
depending on the boolean value represented by the Boolean object.
- valueOf( )
-
Returns the primitive boolean value contained in the Boolean object.
Description
Boolean values are a fundamental data
type in JavaScript. The Boolean object is an object wrapper around
the boolean value. This Boolean object type exists primarily to
provide a toString( ) method to convert boolean
values to strings. When the toString( ) method is
invoked to convert a boolean value to a
string (and it is often invoked
implicitly by JavaScript) JavaScript internally converts the boolean
value to a transient Boolean object, on which the method can be
invoked.
See Also
Object
|