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

How to add JavaScript to html How to enable JavaScript in my browser difference between Java and JavaScript How to call JavaScript function in html How to write a function in JavaScript Is JavaScript case sensitive How does JavaScript Work How to debug JavaScript How to Enable JavaScript on Android What is a promise in JavaScript What is hoisting in JavaScript What is Vanilla JavaScript How to add a class to an element using JavaScript How to calculate the perimeter and area of a circle using JavaScript How to create an image map in JavaScript How to find factorial of a number in JavaScript How to get the value of PI using JavaScript How to make a text italic using JavaScript What are the uses of JavaScript How to get all checked checkbox value in JavaScript How to open JSON file Random image generator in JavaScript How to add object in array using JavaScript JavaScript Window open method JavaScript Window close method How to check a radio button using JavaScript JavaScript Const JavaScript function to check array is empty or not JavaScript multi-line String JavaScript Anonymous Functions Implementing JavaScript Stack Using Array JavaScript classList JavaScript Code Editors JavaScript let keyword Random String Generator using JavaScript JavaScript Queue Event Bubbling and Capturing in JavaScript How to select all checkboxes using JavaScript JavaScript change Event JavaScript focusout event Traverse array object using JavaScript JavaScript create and download CSV file How to make beep sound in JavaScript How to add a WhatsApp share button in a website using JavaScript JavaScript Execution Context JavaScript querySelector Shallow Copy in JavaScript How to Toggle Password Visibility in JavaScript Removing Duplicate From Arrays JavaScript insertBefore JavaScript Select Option Get and Set Scroll Position of an Element Getting Child Elements of a Node in JavaScript JavaScript scrollIntoView JavaScript String startsWith JS First Class Function JavaScript Default Parameters JavaScript Recursion in Real Life JavaScript removeChild Remove options from select list in JavaScript JavaScript Calculator Palindrome in JavaScript JavaScript Call Stack Fibonacci series in JavaScript JavaScript appendchild() method Ripple effect JavaScript Convert object to array in Javascript JavaScript Async/Await JavaScript Blob Check if the array is empty or null, or undefined in JavaScript JavaScript Animation JavaScript Design Patterns CanvasJS JavaScript format numbers with commas Currying in JavaScript JavaScript hasOwnProperty How to make a curved active tab in the navigation menu using HTML CSS and JavaScript Http Cookies JavaScript Comparison JavaScript Confirm JavaScript Garbage JavaScript Special Characters JavaScript Time Now Lodash_.chain() Method Underscore.js _.filter Function JavaScript Factory Function JavaScript for...in Loop Window Location in JavaScript JavaScript Certification Free JavaScript MutationObserver function Npm uninstall command Npm Update Library and Npm List Backend Project Ideas How to become a Front-End Developer Create a JavaScript Countdown Timer Detect or Check Caps Lock Key is ON or OFF using JavaScript How to Iterate through a JavaScript Object JavaScript Fetch API Javascript history.pushState() Method JavaScript Infinity PROPERTY JavaScript insertAdjacentHTML() method How to use Console in JavaScript Insert data into javascript indexedDB JavaScript Exponentiation Operator JavaScript indexedDB Javascript offsetX property Javascript offsetY property JavaScript onunload Event JAVASCRIPT TRIGGER CLICK npm Install Command How to check empty objects in JavaScript How to Check the Specific Element in the JavaScript Class JavaScript NaN Function JavaScript onbeforeunload Event Read Data from JavaScript IndexedDB Delete data from javascript indexedDB NextSibling Property in Javascript PreviousSibling Property in Javascript JavaScript sessionStorage previousElementSibling Property in javascript Base64 Decoding In JavaScript How to get domain name from URL in JavaScript

Lodash

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

Interview Questions

JavaScript I/Q

JavaScript Global Variable

A JavaScript global variable is declared outside the function or declared with window object. It can be accessed from any function.

Let’s see the simple example of global variable in JavaScript.

<script> var value=50;//global variable function a(){ alert(value); function b(){ alert(value); </script> Test it Now

Declaring JavaScript global variable within function

To declare JavaScript global variables inside function, you need to use window object . For example:

window.value=90;

Now it can be declared inside any function and can be accessed from any function. For example:

function m(){ window.value=100;//declaring global variable by window object function n(){ alert(window.value);//accessing global variable from other function Test it Now

Internals of global variable in JavaScript

When you declare a variable outside the function, it is added in the window object internally. You can access it through window object also. For example:

var value=50; function a(){ alert(window.value);//accessing global variable Next Topic JavaScript Data Types