Este objeto nos permite crear un tipo booleano, es decir, verdadero o falso , tomando valores verdaderos o falsos. Podemos crear estos objetos a través de sus constructores. Veamos algunos ejemplos:

a = new Boolean (); Asigna un valor 'falso'

a = new Boolean (0); Asigna un valor 'falso'

a = new Boolean (""); Asigna un valor 'falso'

a = new Boolean (false); Asigna un valor 'falso'

a = new Boolean (0_name); Asigna un valor "verdadero"

a = new Boolean (true); Asigna un valor "verdadero"

Boolean Values

Very often, in programming, you will need a data type that can only have one of two values, like

• YES / NO
• ON / OFF
• TRUE / FALSE

For this, JavaScript has a Boolean data type. It can only take the values true or false.

The Boolean() Function

You can use the Boolean() function to find out if an expression (or a variable) is true:

Example

Boolean(10 > 9) // returns true

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Or even easier:

Example

(10 > 9) // also returns true

10 > 9 // also returns true

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Comparisons and Conditions

The chapter JS comparisons gives a full overview of comparison operators.

The chapter JS conditions gives a full overview of conditional statements.

Here are some examples:

Everything With a Real Value is True

Examples

100

3.14

-15

"Hello"

"false"

7 + 1 + 3.14

5 < 6

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Everything Without a Real Value is False

The Boolean value of 0 (zero) is false:

var x = 0;

Boolean(x); // returns false

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The Boolean value of -0 (minus zero) is false:

var x = -0;

Boolean(x); // returns false

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The Boolean value of "" (empty string) is false:

var x = "";

Boolean(x); // returns false

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The Boolean value of undefined is false:

var x;

Boolean(x); // returns false

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The Boolean value of null is false:

var x = null;

Boolean(x); // returns false

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The Boolean value of false is (you guessed it) false:

var x = false;

Boolean(x); // returns false

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The Boolean value of NaN is false:

var x = 10 / "H";

Boolean(x); // returns false

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Boolean Properties and Methods

Primitive values, like true and false, cannot have properties or methods (because they are not objects).

But with JavaScript, methods and properties are also available to primitive values, because JavaScript treats primitive values as objects when executing methods and properties.

Complete Boolean Reference

For a complete reference, go to our Complete JavaScript Boolean Reference.

The reference contains descriptions and examples of all Boolean properties and methods.

JavaScript Comparison and Logical Operators

Comparison and Logical operators are used to test for true or false.

Comparison Operators

Comparison operators are used in logical statements to determine equality or difference between variables or values.

Given that x=5, the table below explains the comparison operators:

How Can it be Used

Comparison operators can be used in conditional statements to compare values and take action depending on the result:

if (age < 18) text = "Too young";

You will learn more about the use of conditional statements in the next chapter of this tutorial.

Logical Operators

Logical operators are used to determine the logic between variables or values.

Given that x=6 and y=3, the table below explains the logical operators:

Conditional Operator

JavaScript also contains a conditional operator that assigns a value to a variable based on some condition.

Syntax

variablename = (condition) ? value1:value2

Example

voteable = (age < 18) ? "Too young":"Old enough";

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If the variable age is a value below 18, the value of the variable voteable will be "Too young", otherwise the value of voteable will be "Old enough".

JavaScript Bitwise Operators

Bit operators work on 32 bits numbers.

Any numeric operand in the operation is converted into a 32 bit number.

The result is converted back to a JavaScript number.

Example

x = 5 & 1;

The result in x:

1

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