Home
JavaScript
HTML
CSS
Bootstrap
jQuery
Node.js
PHP
Python
C
C++
Java
C#
SQL
Android
Interview Q

JavaScript Tutorial

JavaScript Introduction JavaScript Example External JavaScript

JavaScript Basics

JS Comment JS Variable JS Global Variable JS Data Types JS Operators JS If Statement JS Switch JS Loop JS Function

JavaScript Objects

JS Object JS Array JS String JS Date JS Math JS Number JS Boolean

JavaScript BOM

Browser Objects 1) Window Object 2) History Object 3) Navigator Object 4) Screen Object

JavaScript DOM

5) Document Object getElementById GetElementsByClassName() getElementsByName getElementsByTagName JS innerHTML property JS innerText property

JavaScript Validation

JS form validation JS email validation

JavaScript OOPs

JS Class JS Object JS Prototype JS constructor Method JS static Method JS Encapsulation JS Inheritance JS Polymorphism JS Abstraction

JavaScript Cookies

JS Cookies Cookie Attributes Cookie with multiple Name Deleting Cookies

JavaScript Events

JavaScript Events JavaScript addEventListener() JS onclick event JS dblclick event JS onload event JS onresize event

Exception Handling

JS Exception Handling JavaScript try-catch

JavaScript Misc

JS this Keyword JS Debugging JS Hoisting JS Strict Mode JavaScript Promise JS Compare dates JavaScript array.length JavaScript alert() JavaScript eval() function JavaScript closest() JavaScript continue statement JS getAttribute() method JS hide elements JavaScript prompt() removeAttribute() method JavaScript reset JavaScript return JS String split() JS typeof operator JS ternary operator JS reload() method JS setAttribute() method JS setInterval() method JS setTimeout() method JS string includes() method Calculate current week number in JavaScript Calculate days between two dates in JavaScript JavaScript String trim() JavaScript timer Remove elements from array JavaScript localStorage JavaScript offsetHeight Confirm password validation Static vs Const How to Convert Comma Separated String into an Array in JavaScript Calculate age using JavaScript JavaScript label statement JavaScript String with quotes How to create dropdown list using JavaScript How to disable radio button using JavaScript Check if the value exists in Array in Javascript Javascript Setinterval JavaScript Debouncing JavaScript print() method JavaScript editable table CanvasJS

JavaScript Advance

JS TypedArray JS Set JS Map JS WeakSet JS WeakMap JavaScript callback JavaScript closures JavaScript date difference JavaScript date format JS date parse() method JavaScript defer JavaScript redirect JavaScript scope JavaScript scroll JavaScript sleep JavaScript void JavaScript Form

Differences

jQuery vs JavaScript JavaScript vs PHP Dart vs. JavaScript JavaScript Vs. Angular Js JavaScript vs. Node.js

Questions

Lodash

Lodash _.find() Method Lodash_.get() Method

MCQ

JavaScript MCQ

Interview Questions

JavaScript I/Q

next → ← prev

JavaScript Map keys() method

The JavaScript map keys() method returns an object of new Map iterator. This object contains the key for each element. It maintains insertion order.

Syntax

The keys() method is represented by the following syntax:

Return

A new object of Map iterator.

JavaScript Map keys() method example

Here, we will understand keys() method through various examples.

Example 1

Let's see a simple example of keys() method.

<script>
var map=new Map();
map.set(1,"jQuery");
map.set(2,"AngularJS");
map.set(3,"Bootstrap");
var itr=map.keys();
document.writeln(itr.next().value+"<br>");
document.writeln(itr.next().value+"<br>");
document.writeln(itr.next().value);
 </script>

Test it Now

Output:

1
2
3

Example 2

Let's see the same example using for loop.

<script>
var map=new Map();
map.set(1,"jQuery");
map.set(2,"AngularJS");
map.set(3,"Bootstrap");
var itr=map.keys();
for(i=0;i<map.size;i++)
  {
document.writeln(itr.next().value+"<br>");
  }
  </script>

Test it Now

Output:

1
2
3

Next TopicJavaScript Math

← prev next →

For Videos Join Our Youtube Channel: Join Now

Feedback

Send your Feedback to [email protected]

Help Others, Please Share

Learn Latest Tutorials

Splunk

SPSS

Swagger

Transact-SQL

Tumblr

ReactJS

Regex

Reinforcement Learning

R Programming

RxJS

React Native

Python Design Patterns

Python Pillow

Python Turtle

Keras

Preparation

Aptitude

Reasoning

Verbal Ability

Interview Questions

Company Questions

Trending Technologies

Artificial Intelligence

AWS

Selenium

Cloud Computing

Hadoop

ReactJS

Data Science

Angular 7

Blockchain

Git

Machine Learning

DevOps

B.Tech / MCA

DBMS

Data Structures

DAA

Operating System

Computer Network

Compiler Design

Computer Organization

Discrete Mathematics

Ethical Hacking

Computer Graphics

Software Engineering

Web Technology

Cyber Security

Automata

C Programming

C++

Java

.Net

Python

Programs

Control System

Data Mining

Data Warehouse

^{Like/Subscribe us for latest updates or newsletter}

Learn Tutorials

Learn Java Learn Data Structures Learn C Programming Learn C++ Tutorial Learn C# Tutorial Learn PHP Tutorial Learn HTML Tutorial Learn JavaScript Tutorial Learn jQuery Tutorial Learn Spring Tutorial

Interview Questions

Java Interview Questions SQL Interview Questions Python Interview Questions JavaScript Interview Questions Angular Interview Questions Selenium Interview Questions Spring Boot Interview Questions HR Interview Questions C++ Interview Questions Data Structure Interview Questions

About

Javatpoint is developed to help students on various technologies such as Artificial Intelligence, Machine Learning, C, C++, Python, Java, PHP, HTML, CSS, JavaScript, jQuery, ReactJS, Node.js, AngularJS, Bootstrap, XML, SQL, PL/SQL, MySQL etc.

Javatpoint provides tutorials with examples, code snippets, and practical insights, making it suitable for both beginners and experienced developers.

There are also many interview questions which will help students to get placed in the companies.

Contact

Address: G-13, 2nd Floor, Sec-3

Noida, UP, 201301, India

Contact No: 0120-4256464, 9990449935