Cara menggunakan javascript boolean variable declaration

Boolean is a datatype that returns either of two values i.e. true or false. In JavaScript, Boolean is used as a function to get the value of a variable, object, conditions, expressions, etc. in terms of true or false.

Note: A variable or object which has a value is treated as a true boolean value. ‘0’, ‘NaN’, empty string, ‘undefined’, and ‘null’ is treated as false boolean values. 

Here a1 and a2 store the boolean value i.e. true and false respectively. 

var a1 = true; var a2 = false;

Note: Below variables are initialized with strings not boolean values.  

var a1 ="true"; var a2 ="false";

Boolean() function in JavaScript: Boolean function returns the boolean value of the variable. It can also be used to find the boolean result of a condition, expression, etc.

Syntax:  

Boolean(variable/expression)

JavaScript Boolean object: The boolean object in javascript is an object wrapper for boolean values. Booleans in JavaScript can also be defined using the new keyword. 

Syntax:  

new Boolean(value)

Below are examples of the JavaScript Boolean method.

Example 1: Below program will give true values as output

javascript

function var a1 ="true"; var a2 ="false";0

var a1 ="true"; var a2 ="false";1var a1 ="true"; var a2 ="false";2

var a1 ="true"; var a2 ="false";3

var a1 ="true"; var a2 ="false";4

Output: 

true

Example 2:

Javascript

var a1 ="true"; var a2 ="false";5var a1 ="true"; var a2 ="false";6 var a1 ="true"; var a2 ="false";7

var a1 ="true"; var a2 ="false";5var a1 ="true"; var a2 ="false";9 

Boolean(variable/expression) 0Boolean(variable/expression) 1Boolean(variable/expression) 2Boolean(variable/expression) 3

var a1 ="true"; var a2 ="false";5Boolean(variable/expression) 5 Boolean(variable/expression) 6

var a1 ="true"; var a2 ="false";5Boolean(variable/expression) 8 Boolean(variable/expression) 9

var a1 ="true"; var a2 ="false";5new Boolean(value)1 Boolean(variable/expression) 1new Boolean(value)3Boolean(variable/expression) 3

var a1 ="true"; var a2 ="false";5new Boolean(value)6 Boolean(variable/expression) 1new Boolean(value)8Boolean(variable/expression) 3

var a1 ="true"; var a2 ="false";5true1 

Boolean(variable/expression) 0true3

var a1 ="true"; var a2 ="false";5true5 true6

Output: 

Boolean(10) is true Boolean("GeeksforGeeks") is true Boolean(2.74) is true Boolean(-1) is true Boolean('true') is true Boolean('false') is true Boolean(3 * 2 + 1.11) is true Boolean(1<2) is true

Example 3: Below program will give false values as output.  

javascript

true7 true8true9

var a1 ="true"; var a2 ="false";5Boolean(10) is true Boolean("GeeksforGeeks") is true Boolean(2.74) is true Boolean(-1) is true Boolean('true') is true Boolean('false') is true Boolean(3 * 2 + 1.11) is true Boolean(1<2) is true1 Boolean(10) is true Boolean("GeeksforGeeks") is true Boolean(2.74) is true Boolean(-1) is true Boolean('true') is true Boolean('false') is true Boolean(3 * 2 + 1.11) is true Boolean(1<2) is true2

var a1 ="true"; var a2 ="false";5Boolean(10) is true Boolean("GeeksforGeeks") is true Boolean(2.74) is true Boolean(-1) is true Boolean('true') is true Boolean('false') is true Boolean(3 * 2 + 1.11) is true Boolean(1<2) is true4 Boolean(variable/expression) 1Boolean(10) is true Boolean("GeeksforGeeks") is true Boolean(2.74) is true Boolean(-1) is true Boolean('true') is true Boolean('false') is true Boolean(3 * 2 + 1.11) is true Boolean(1<2) is true6Boolean(variable/expression) 3

var a1 ="true"; var a2 ="false";5Boolean(10) is true Boolean("GeeksforGeeks") is true Boolean(2.74) is true Boolean(-1) is true Boolean('true') is true Boolean('false') is true Boolean(3 * 2 + 1.11) is true Boolean(1<2) is true9 

Boolean(variable/expression) 0Boolean(0) is false Boolean("") is false Boolean(e) undefined is false Boolean(-0) is false Boolean(false) is false Boolean(NaN) is false Boolean(null) is false Boolean(1>2) is false1

var a1 ="true"; var a2 ="false";5Boolean(0) is false Boolean("") is false Boolean(e) undefined is false Boolean(-0) is false Boolean(false) is false Boolean(NaN) is false Boolean(null) is false Boolean(1>2) is false3 Boolean(0) is false Boolean("") is false Boolean(e) undefined is false Boolean(-0) is false Boolean(false) is false Boolean(NaN) is false Boolean(null) is false Boolean(1>2) is false4

var a1 ="true"; var a2 ="false";5Boolean(0) is false Boolean("") is false Boolean(e) undefined is false Boolean(-0) is false Boolean(false) is false Boolean(NaN) is false Boolean(null) is false Boolean(1>2) is false6 Boolean(variable/expression) 1Boolean(0) is false Boolean("") is false Boolean(e) undefined is false Boolean(-0) is false Boolean(false) is false Boolean(NaN) is false Boolean(null) is false Boolean(1>2) is false8Boolean(variable/expression) 3

var a1 ="true"; var a2 ="false";5v1 = false v2 = false v3 = false v4 = false v5 = true v6 = true1 v1 = false v2 = false v3 = false v4 = false v5 = true v6 = true2

var a1 ="true"; var a2 ="false";5v1 = false v2 = false v3 = false v4 = false v5 = true v6 = true4 Boolean(variable/expression) 1v1 = false v2 = false v3 = false v4 = false v5 = true v6 = true6Boolean(variable/expression) 3

var a1 ="true"; var a2 ="false";5v1 = false v2 = false v3 = false v4 = false v5 = true v6 = true9 v1 = = v2 is true v1 = = = v2 is false0

Output: 

Boolean(0) is false Boolean("") is false Boolean(e) undefined is false Boolean(-0) is false Boolean(false) is false Boolean(NaN) is false Boolean(null) is false Boolean(1>2) is false

Example 4:  

javascript

true7 v1 = = v2 is true v1 = = = v2 is false2Boolean(0) is false Boolean("") is false Boolean(e) undefined is false Boolean(-0) is false Boolean(false) is false Boolean(NaN) is false Boolean(null) is false Boolean(1>2) is false8v1 = = v2 is true v1 = = = v2 is false4

true7 v1 = = v2 is true v1 = = = v2 is false6v1 = = v2 is true v1 = = = v2 is false7 v1 = = v2 is true v1 = = = v2 is false8Boolean(0) is false Boolean("") is false Boolean(e) undefined is false Boolean(-0) is false Boolean(false) is false Boolean(NaN) is false Boolean(null) is false Boolean(1>2) is false8function0

true7 function2v1 = = v2 is true v1 = = = v2 is false7 v1 = = v2 is true v1 = = = v2 is false8Boolean(10) is true Boolean("GeeksforGeeks") is true Boolean(2.74) is true Boolean(-1) is true Boolean('true') is true Boolean('false') is true Boolean(3 * 2 + 1.11) is true Boolean(1<2) is true6function0

true7 function8v1 = = v2 is true v1 = = = v2 is false7 var a1 ="true"; var a2 ="false";00

true7 var a1 ="true"; var a2 ="false";02v1 = = v2 is true v1 = = = v2 is false7 v1 = = v2 is true v1 = = = v2 is false8var a1 ="true"; var a2 ="false";05function0

true7 var a1 ="true"; var a2 ="false";08v1 = = v2 is true v1 = = = v2 is false7 v1 = = v2 is true v1 = = = v2 is false8Boolean(variable/expression) 2function0

var a1 ="true"; var a2 ="false";13var a1 ="true"; var a2 ="false";14 var a1 ="true"; var a2 ="false";15

var a1 ="true"; var a2 ="false";13var a1 ="true"; var a2 ="false";17 var a1 ="true"; var a2 ="false";18

var a1 ="true"; var a2 ="false";13var a1 ="true"; var a2 ="false";20 var a1 ="true"; var a2 ="false";21

var a1 ="true"; var a2 ="false";13var a1 ="true"; var a2 ="false";23 var a1 ="true"; var a2 ="false";24

var a1 ="true"; var a2 ="false";13var a1 ="true"; var a2 ="false";26 var a1 ="true"; var a2 ="false";27

var a1 ="true"; var a2 ="false";13var a1 ="true"; var a2 ="false";29 var a1 ="true"; var a2 ="false";30

Output:  

v1 = false v2 = false v3 = false v4 = false v5 = true v6 = true

Example 5:  

javascript

true7 v1 = = v2 is true v1 = = = v2 is false2var a1 ="true"; var a2 ="false";05v1 = = v2 is true v1 = = = v2 is false4

true7 v1 = = v2 is true v1 = = = v2 is false6v1 = = v2 is true v1 = = = v2 is false7 v1 = = v2 is true v1 = = = v2 is false8var a1 ="true"; var a2 ="false";05function0

var a1 ="true"; var a2 ="false";41 

var a1 ="true"; var a2 ="false";5var a1 ="true"; var a2 ="false";43 var a1 ="true"; var a2 ="false";44

var a1 ="true"; var a2 ="false";5var a1 ="true"; var a2 ="false";46 var a1 ="true"; var a2 ="false";47

Output: 

v1 = = v2 is true v1 = = = v2 is false

Note: v1 = = = v2 is not true as the type of v1 and v2(object) is not the same.

Supported Browsers:

• Google Chrome 6 and above
• Edge 12 and above
• Firefox 4 and above
• Internet Explorer 9 and above
• Opera 12 and above
• Safari 5.1 and above

We have a Cheat Sheet on Javascript where we covered all the important topics of Javascript to check those please go through Javascript Cheat Sheet-A Basic guide to JavaScript.

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