{"id":15835,"date":"2024-12-18T13:10:58","date_gmt":"2024-12-18T07:40:58","guid":{"rendered":"https:\/\/www.w3webschool.com\/blog\/?p=15835"},"modified":"2024-12-18T13:12:26","modified_gmt":"2024-12-18T07:42:26","slug":"javascript-interview-questions","status":"publish","type":"post","link":"https:\/\/www.w3webschool.com\/blog\/javascript-interview-questions\/","title":{"rendered":"Most-asked 15+ JavaScript Interview Questions and Answers [2025 Updated]"},"content":{"rendered":"\t\t<div data-elementor-type=\"wp-post\" data-elementor-id=\"15835\" class=\"elementor elementor-15835\" data-elementor-post-type=\"post\">\n\t\t\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-679c434 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"679c434\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-6883df5\" data-id=\"6883df5\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-7987361 elementor-widget elementor-widget-hfe-breadcrumbs-widget\" data-id=\"7987361\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"hfe-breadcrumbs-widget.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<nav aria-label=\"Breadcrumb\"><ul class=\"hfe-breadcrumbs hfe-breadcrumbs-show-home\"><li class=\"hfe-breadcrumbs-item hfe-breadcrumbs-first\"><span class=\"hfe-breadcrumbs-home-icon\"><\/span><a href=\"https:\/\/www.w3webschool.com\/blog\"><span class=\"hfe-breadcrumbs-text\">Home<\/span><\/a><\/li><\/ul><\/nav>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-e9e6e85 elementor-widget elementor-widget-heading\" data-id=\"e9e6e85\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h1 class=\"elementor-heading-title elementor-size-default\">Most-asked 15+ JavaScript Interview Questions and Answers [2025 Updated]<\/h1>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-68a3669 elementor-widget elementor-widget-image\" data-id=\"68a3669\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<img fetchpriority=\"high\" decoding=\"async\" width=\"1280\" height=\"720\" src=\"data:image\/gif;base64,R0lGODlhAQABAIAAAAAAAP\/\/\/yH5BAEAAAAALAAAAAABAAEAAAIBRAA7\" data-src=\"https:\/\/www.w3webschool.com\/blog\/wp-content\/uploads\/2024\/12\/JavaScript-Interview-Questions.png\" class=\"attachment-full size-full wp-image-15863 lazyload\" alt=\"JavaScript Interview Questions\" data-srcset=\"https:\/\/www.w3webschool.com\/blog\/wp-content\/uploads\/2024\/12\/JavaScript-Interview-Questions.png 1280w, https:\/\/www.w3webschool.com\/blog\/wp-content\/uploads\/2024\/12\/JavaScript-Interview-Questions-300x169.png 300w, https:\/\/www.w3webschool.com\/blog\/wp-content\/uploads\/2024\/12\/JavaScript-Interview-Questions-1100x619.png 1100w, https:\/\/www.w3webschool.com\/blog\/wp-content\/uploads\/2024\/12\/JavaScript-Interview-Questions-768x432.png 768w\" sizes=\"(max-width: 1280px) 100vw, 1280px\" title=\"\"><noscript><img decoding=\"async\" width=\"1280\" height=\"720\" src=\"https:\/\/www.w3webschool.com\/blog\/wp-content\/uploads\/2024\/12\/JavaScript-Interview-Questions.png\" class=\"attachment-full size-full wp-image-15863 lazyload\" alt=\"JavaScript Interview Questions\" srcset=\"https:\/\/www.w3webschool.com\/blog\/wp-content\/uploads\/2024\/12\/JavaScript-Interview-Questions.png 1280w, 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class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-c9369ce\" data-id=\"c9369ce\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<section class=\"elementor-section elementor-inner-section elementor-element elementor-element-04e043c elementor-section-full_width elementor-section-height-default elementor-section-height-default\" data-id=\"04e043c\" data-element_type=\"section\" data-e-type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-33 elementor-inner-column elementor-element elementor-element-5e852ea\" data-id=\"5e852ea\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-14c7c90 elementor-share-buttons--view-icon elementor-share-buttons--skin-flat elementor-share-buttons--shape-rounded elementor-share-buttons--align-left elementor-grid-0 elementor-share-buttons--color-official elementor-widget elementor-widget-share-buttons\" data-id=\"14c7c90\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"share-buttons.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<div class=\"elementor-grid\">\n\t\t\t\t\t\t\t\t<div class=\"elementor-grid-item\">\n\t\t\t\t\t\t<div\n\t\t\t\t\t\t\tclass=\"elementor-share-btn elementor-share-btn_facebook\"\n\t\t\t\t\t\t\trole=\"button\"\n\t\t\t\t\t\t\ttabindex=\"0\"\n\t\t\t\t\t\t\taria-label=\"Share on facebook\"\n\t\t\t\t\t\t>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-share-btn__icon\">\n\t\t\t\t\t\t\t\t<i class=\"fab fa-facebook\" aria-hidden=\"true\"><\/i>\t\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t<div class=\"elementor-grid-item\">\n\t\t\t\t\t\t<div\n\t\t\t\t\t\t\tclass=\"elementor-share-btn elementor-share-btn_twitter\"\n\t\t\t\t\t\t\trole=\"button\"\n\t\t\t\t\t\t\ttabindex=\"0\"\n\t\t\t\t\t\t\taria-label=\"Share on twitter\"\n\t\t\t\t\t\t>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-share-btn__icon\">\n\t\t\t\t\t\t\t\t<i class=\"fab fa-twitter\" aria-hidden=\"true\"><\/i>\t\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t<div class=\"elementor-grid-item\">\n\t\t\t\t\t\t<div\n\t\t\t\t\t\t\tclass=\"elementor-share-btn elementor-share-btn_linkedin\"\n\t\t\t\t\t\t\trole=\"button\"\n\t\t\t\t\t\t\ttabindex=\"0\"\n\t\t\t\t\t\t\taria-label=\"Share on linkedin\"\n\t\t\t\t\t\t>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-share-btn__icon\">\n\t\t\t\t\t\t\t\t<i class=\"fab fa-linkedin\" aria-hidden=\"true\"><\/i>\t\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t<div class=\"elementor-grid-item\">\n\t\t\t\t\t\t<div\n\t\t\t\t\t\t\tclass=\"elementor-share-btn elementor-share-btn_whatsapp\"\n\t\t\t\t\t\t\trole=\"button\"\n\t\t\t\t\t\t\ttabindex=\"0\"\n\t\t\t\t\t\t\taria-label=\"Share on whatsapp\"\n\t\t\t\t\t\t>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-share-btn__icon\">\n\t\t\t\t\t\t\t\t<i class=\"fab fa-whatsapp\" aria-hidden=\"true\"><\/i>\t\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t<div class=\"elementor-grid-item\">\n\t\t\t\t\t\t<div\n\t\t\t\t\t\t\tclass=\"elementor-share-btn elementor-share-btn_email\"\n\t\t\t\t\t\t\trole=\"button\"\n\t\t\t\t\t\t\ttabindex=\"0\"\n\t\t\t\t\t\t\taria-label=\"Share on email\"\n\t\t\t\t\t\t>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-share-btn__icon\">\n\t\t\t\t\t\t\t\t<i class=\"fas fa-envelope\" aria-hidden=\"true\"><\/i>\t\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-8e2482d elementor-hidden-tablet elementor-hidden-mobile elementor-toc--minimized-on-tablet elementor-widget elementor-widget-table-of-contents\" data-id=\"8e2482d\" data-element_type=\"widget\" data-e-type=\"widget\" data-settings=\"{&quot;headings_by_tags&quot;:[&quot;h2&quot;,&quot;h3&quot;],&quot;exclude_headings_by_selector&quot;:[],&quot;marker_view&quot;:&quot;bullets&quot;,&quot;min_height_tablet&quot;:{&quot;unit&quot;:&quot;vh&quot;,&quot;size&quot;:&quot;&quot;,&quot;sizes&quot;:[]},&quot;min_height_mobile&quot;:{&quot;unit&quot;:&quot;vh&quot;,&quot;size&quot;:&quot;&quot;,&quot;sizes&quot;:[]},&quot;sticky_offset&quot;:80,&quot;sticky&quot;:&quot;top&quot;,&quot;sticky_on&quot;:[&quot;desktop&quot;],&quot;sticky_parent&quot;:&quot;yes&quot;,&quot;icon&quot;:{&quot;value&quot;:&quot;fas fa-circle&quot;,&quot;library&quot;:&quot;fa-solid&quot;},&quot;minimize_box&quot;:&quot;yes&quot;,&quot;minimized_on&quot;:&quot;tablet&quot;,&quot;min_height&quot;:{&quot;unit&quot;:&quot;px&quot;,&quot;size&quot;:&quot;&quot;,&quot;sizes&quot;:[]},&quot;sticky_effects_offset&quot;:0}\" data-widget_type=\"table-of-contents.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<div class=\"elementor-toc__header\">\n\t\t\t<h4 class=\"elementor-toc__header-title\">\n\t\t\t\tTable of Contents\t\t\t<\/h4>\n\t\t\t\t\t\t\t<div class=\"elementor-toc__toggle-button elementor-toc__toggle-button--expand\" role=\"button\" tabindex=\"0\" aria-controls=\"elementor-toc__8e2482d\" aria-expanded=\"true\" aria-label=\"Open table of contents\"><i aria-hidden=\"true\" class=\"fas fa-chevron-down\"><\/i><\/div>\n\t\t\t\t<div class=\"elementor-toc__toggle-button elementor-toc__toggle-button--collapse\" role=\"button\" tabindex=\"0\" aria-controls=\"elementor-toc__8e2482d\" aria-expanded=\"true\" aria-label=\"Close table of contents\"><i aria-hidden=\"true\" class=\"fas fa-chevron-up\"><\/i><\/div>\n\t\t\t\t\t<\/div>\n\t\t<div id=\"elementor-toc__8e2482d\" class=\"elementor-toc__body\">\n\t\t\t<div class=\"elementor-toc__spinner-container\">\n\t\t\t\t<i class=\"elementor-toc__spinner eicon-animation-spin eicon-loading\" aria-hidden=\"true\"><\/i>\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t<div class=\"elementor-column elementor-col-33 elementor-inner-column elementor-element elementor-element-9c40480\" data-id=\"9c40480\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-4bba3d4 elementor-widget elementor-widget-text-editor\" data-id=\"4bba3d4\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p><span style=\"font-weight: 400;\">Are you brushing yourself for a JavaScript interview in 2025? It can be a little bit challenging as there are a huge amount of concepts to learn and remember! Are you feeling nervous about how many topics you have to brush up on for your next interview?\u00a0<\/span><\/p><p><span style=\"font-weight: 400;\">Don&#8217;t stress over this! I have come up with a solution to clear your doubts regarding this.\u00a0<\/span><\/p><p><span style=\"font-weight: 400;\">In this blog post, I will discuss the most-asked 15+ JavaScript interview questions for candidates who want to start their professional journey in the development field, as well as experienced candidates willing to upskill in simple terms. You will have a complete idea of this programming language and know how to respond to hiring managers when they ask you questions on this topic.<\/span><\/p><p><span style=\"font-weight: 400;\">Whether you are a newbie or a professional developer, these latest questions will guide you to become industry-ready and crack the interviews in 2025.\u00a0<\/span><\/p><p><span style=\"font-weight: 400;\">Let&#8217;s begin by diving into the list of interview questions and make yourself industry ready!<\/span><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-6ad53c9 elementor-widget elementor-widget-heading\" data-id=\"6ad53c9\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">List Of Top 15+ JavaScript Interview Questions and Answers\n<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-f91397c elementor-widget elementor-widget-text-editor\" data-id=\"f91397c\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p><span style=\"font-weight: 400;\">I have prepared a detailed list of <\/span><b>the Top 15+ JavaScript interview questions<\/b><span style=\"font-weight: 400;\"> and answers to guide you in impressing the hiring managers. I have picked each <\/span><a href=\"https:\/\/www.w3webschool.com\/full-stack-web-development-course-in-kolkata\/\"><b>JavaScript interview question<\/b><\/a><span style=\"font-weight: 400;\"> carefully by taking guidance from development professionals depending on what might be asked in the next interviews.\u00a0<\/span><\/p><p><span style=\"font-weight: 400;\">Read this article thoroughly and increase your opportunities of cracking the development interviews. This blog post will offer you a concrete overview of JavaScript, a popular programming language.\u00a0\u00a0<\/span><\/p><p><span style=\"font-weight: 400;\">Let&#8217;s start this,\u00a0<\/span><\/p><p><b>Q 1. What do you mean by JavaScript?<\/b><\/p><p><span style=\"font-weight: 400;\">The most dynamic programming language, JavaScript, is majorly applied for creating versatile and highly user-intuitive websites. This enables developers to make responsive pages to different user activities such as typing, clicks and movements of the mouse. JavaScript is specially applied to manipulate page elements, animate graphics, manage multimedia and validate different forms. This runs within the web browser.\u00a0<\/span><\/p><p><b>Q 2. What are the different types of data supported by JavaScript?<\/b><\/p><p><span style=\"font-weight: 400;\">There are different types of data supported by JavaScript, and they are Primitive data types and Non-primitive data types.<\/span><\/p><p><span style=\"font-weight: 400;\">Primitive data types are those that can be immutable. Strings, null, undefined, numbers, Biglnt, booleans and symbols are among primitive data types.<\/span><\/p><p><span style=\"font-weight: 400;\">On the other hand, Non-primitive data types are those that store sets of data or different functionalities. Functions, objects and arrays are among non-primitive data types.<\/span><\/p><p><b>Q 3. What are events in JavaScript?<\/b><\/p><p><span style=\"font-weight: 400;\">Events in JavaScript are referred to as activities or functions that occur on a web page. Some instances of Events are form submission, clicking a button, pressing a key, and more! JavaScript enables web developers to manage such Events with the assistance of Event Listeners. For instance, you can run a function while a user makes a click. Such Events help a web page become highly engaging and versatile.<\/span><\/p><p><b>Q 4. What are Closures in JavaScript?<\/b><\/p><p><span style=\"font-weight: 400;\">The function Closure in JavaScript is used to remember the parent functions and variables that are highlighted in its outside area. This is remembered even after the task has been conducted and completed. It enables easy access to the outside function&#8217;s variables from the inside section.<\/span><\/p><p><b>Q 5. Differentiate Regular functions from Arrow functions.<\/b><\/p><p><span style=\"font-weight: 400;\">In JavaScript, Regular functions are known as to the element that calls them so that they can have their separate setting. For some cases, Arrow functions are simpler and more brief as they take this from the adjacent code rather than owning it themselves.<\/span><\/p><p><b>Q 6. Can you state the benefits of using JavaScript?<\/b><\/p><p><span style=\"font-weight: 400;\">There are plenty of benefits of this dynamic programming language, and they are;<\/span><\/p><ul><li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">This is easy to use.<\/span><\/li><li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">JavaScript is way faster than other languages and can manage complex calculations. Due to its function of client-side code execution, it is speedier than other server-side languages.<\/span><\/li><li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">It has built-in security features due to Angular and React frameworks.<\/span><\/li><li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">It is a very lightweight programming language; hence, there is no need to install heavy software.\u00a0<\/span><\/li><li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">JavaScript offers cross-browser compatibility.<\/span><\/li><li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">It offers broad library support.<\/span><\/li><li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">This is interactive and dynamic and can handle features such as mouse movements, clicks and keyboard inputs.<\/span><\/li><li style=\"font-weight: 400;\" aria-level=\"1\"><span style=\"font-weight: 400;\">It supports third-party add-ons, making it easier for developers to create stunning JavaScript applications.<\/span><\/li><\/ul><p><b>Q 7. Can you explain the functionality of the type of operator?<\/b><\/p><p><span style=\"font-weight: 400;\">The type of operator in JavaScript is employed to figure out the type of a variable. It assists in guaranteeing that specific variables are used correctly by offering a string that defines the type of the operand including &#8216;number&#8217;, &#8216;boolean&#8217; and &#8216;string&#8217;. This is a popular type-checking operator and it helps in returning the string that indicates the specific type of operand one passes to it.\u00a0<\/span><\/p><p><b>Q 8. State the difference between defined and not defined.<\/b><\/p><p><span style=\"font-weight: 400;\">The element variable in JavaScript is considered to be &#8216;defined&#8217; when it has been stated and assigned a value. Viewing the variable in your code will enable you to check this. When a variable is &#8216;not defined&#8217;\u2014that is, not clearly declared\u2014any request to access it will end in a ReferenceError. It is also acceptable for the variable to be set up but not configured, in which event it has been defined, but its actual value is undefined.<\/span><\/p><p><b>Q 9. What do you mean by Strict Mode?<\/b><\/p><p><span style=\"font-weight: 400;\">The Strict Mode in JavaScript refers to the specific mode that enables you to select a more demanding version of the programming language. It eliminates some harmful features and boosts the amount of errors that JavaScript delivers. For example, it prevents deployments to read-only attributes and the employ only of variables that are undeclared. This also limits programmers in making code that is simple and less likely to have errors. By inserting &#8216;use strict&#8217; at the start of your program or function, you will be able to activate the Strict Mode.<\/span><\/p><p><b>Q 10. Can you differentiate search from indexOf?<\/b><\/p><p><span style=\"font-weight: 400;\">Yes, I can.\u00a0<\/span><\/p><p><span style=\"font-weight: 400;\">However, both of them are applied to search within a string, and the search() and indexOf() function in different ways. The position of a substring&#8217;s initial appearance is returned by indexOf() after searching for it. If the substring will not be able to be located, the returning value is -1. On the other hand, search() employs regular expressions and offers the index of the first match or -1 in the case that no match is found there. As it can manage different patterns, search() is more effective.<\/span><\/p><p><b>Q 11. Explain the differences between an object and an array<\/b><span style=\"font-weight: 400;\">.<\/span><\/p><p><span style=\"font-weight: 400;\">A huge set of key-value pairs, with the specific keys typically being symbols or strings and the values being any data type, is referred to as an object in JavaScript. Objects are not organized in any specific order. On the contrary, arrays are huge sets of values that are organized in a particular sequence and are indexed by specific numbers that initiate at 0. Related data should be stored in objects, while ordered data is stored effectively in arrays. Index places are employed to get easy access to array values, and keys are employed to access the values of objects.\u00a0<\/span><\/p><p><b>Q 12. What do you mean by Hoisting in JavaScript?<\/b><\/p><p><span style=\"font-weight: 400;\">Hoisting in JavaScript refers to the act of relocating function and variable declarations comes first due to their scope before the code execution. This also means that different functions and variables can be addressed before declaration. However, their duties are not triggered; only the declarations are addressed. For example, variables set with a value will be back undefined if used prior to their actual task, while a function can be addressed prior to its declaration even.<\/span><\/p><p><b>Q 13. What are the differences between String() and Substring()?<\/b><span style=\"font-weight: 400;\">\u00a0<\/span><\/p><p><span style=\"font-weight: 400;\">Any data type, like objects, numbers, or booleans, can be transformed into a string with the application of the String() function. It is used to ensure a variable contains a string format. On the contrary, the substring() method eliminates or restricts a section of a string among two specified indices. It does not alter or modify the original string; rather, it returns a new value. Therefore, substring() alters the content of any strings, while String() changes specific data types.<\/span><\/p><p><b>Q 14. State the purpose of the setTimeout() function in JavaScript.<\/b><\/p><p><span style=\"font-weight: 400;\">setTimeout () refers to the specific function of JavaScript that pauses the running of the specific function or code because of a specific amount of time that is predetermined already. This is measured in Milliseconds. It allows a programmer to start a function in a predetermined amount of time.\u00a0<\/span><\/p><p><span style=\"font-weight: 400;\">One function is SetTimeout(() =&gt; alert(&#8220;Hello&#8221;), 3000). This will highlight a notification after three seconds. Time-based functions such as animations, the latest updates, and user interactions can be managed perfectly with its assistance.<\/span><\/p><p><b>Q 15. Can you explain how you can remove duplicates in an array?<\/b><\/p><p><span style=\"font-weight: 400;\">You must apply a Set to remove duplicates in an array from JavaSript. Turning an array to a Set and back to an array removes duplicates, as a set only handles single values by nature. Take uniqueArray = [&#8230;new Set(array)] for instance. Filter() is another major technique that continues through the array, saving just the unique values while contrasting each other.<\/span><\/p><p><b>Q 16. <\/b> <b>Explain the term BOM.<\/b><\/p><p><span style=\"font-weight: 400;\">The term BOM refers to the Browser Object Model. It enables JavaScript to connect with the browser despite the content of the page by reflecting the setting in which a web page is offered. The browser window, location, history, pop-ups, and size can all be managed by employing the techniques and features that the BOM provides. It helps in managing not only the document data but also the functionality of the browser.<\/span><\/p><p><b>Q 17. What do you mean by DOM? State the usability of it.\u00a0<\/b><\/p><p><span style=\"font-weight: 400;\">The term DOM refers to the Document Object Model. This interface highlights the structure of an HTML document as a network of objects. JavaScript automatically uses, alters, and updates the content of the web page with the help of the DOM. Without having to reboot the entire web page, developers can alter HTML tags, attributes, fonts, and formats on the web page by communicating with the DOM.<\/span><\/p><p><b>Q 18. What do you mean by callback function in Java?<\/b><\/p><p><span style=\"font-weight: 400;\">The callback function in JavaScript refers to the function that is executed immediately after receiving data as input to another task. Asynchronous programming often applies it to handle complex functions such as user input waiting and file reading. The callback is launched to complete the task once the primary function has been completed. This makes it feasible to do functions such as API calls or animations without triggering the primary thread to start working.<\/span><\/p><p><b>Q 19. Explain the usage of Window Objects.<\/b><\/p><p><span style=\"font-weight: 400;\">The browser window or tab is depicted by JavaScript&#8217;s Window object. It provides specific features and processes for communicating with the browser setting. It can be employed, for example, to present alarms, adjust the window, new tab launching, and access the dimensions of the browser. As the Window object is open in the browser, any script that is currently running in the browser can have direct access to it.\u00a0<\/span><\/p><p><b>Q 20. Can you state how to create an object in JavaScript?<\/b><\/p><p><span style=\"font-weight: 400;\">With the help of literal notation, you will be able to create an object in JavaScript. This is a very popular and common method for object creation. For instance, let person = { name: &#8216;<\/span> <span style=\"font-weight: 400;\">Paul&#8217;, age: 25};. <\/span><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-513991c elementor-widget elementor-widget-heading\" data-id=\"513991c\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">Wrapping Up,<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-32adaa3 elementor-widget elementor-widget-text-editor\" data-id=\"32adaa3\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p><span style=\"font-weight: 400;\">In this article, I have highlighted the most commonly asked<\/span> <span style=\"font-weight: 400;\">JavaScript Interview Questions in a very simple and straightforward manner. Hoping, this blog post provides you a complete and deep understanding of the range of tricky questions asked in the interviews and will assist you impress your hiring managers with your prompt responses.<\/span><\/p><p><span style=\"font-weight: 400;\">Pick the right course offered by<a href=\"https:\/\/www.w3webschool.com\/\"><strong> W3 Web School<\/strong><\/a>, depending on various features, functions and tasks. The above-mentioned questions and their answers offer a detailed idea of this specific programming language and other major factors to educate candidates to make a wise decision on which course they want to pick and start their career in JavaScript.\u00a0<\/span><\/p><p><span style=\"font-weight: 400;\">Recommended Readings:<\/span><\/p><ul><li style=\"font-weight: 400;\" aria-level=\"1\"><a href=\"https:\/\/www.w3webschool.com\/blog\/wordpress-interview-questions\/\"><span style=\"font-weight: 400;\">15+ Essential WordPress Interview Questions &amp; Answers For 2024<\/span><\/a><\/li><li style=\"font-weight: 400;\" aria-level=\"1\"><a href=\"https:\/\/www.w3webschool.com\/blog\/sql-interview-questions\/\"><span style=\"font-weight: 400;\">Top SQL Interview Questions for Freshers [2025]<\/span><\/a><\/li><li style=\"font-weight: 400;\" aria-level=\"1\"><a href=\"https:\/\/www.w3webschool.com\/blog\/ui-ux-designer-interview-questions\/\"><span style=\"font-weight: 400;\">Top 15+ UI\/UX Designer Interview Questions For Freshers [2024]<\/span><\/a><\/li><li style=\"font-weight: 400;\" aria-level=\"1\"><a href=\"https:\/\/www.w3webschool.com\/blog\/front-end-developer-interview-questions\/\"><span style=\"font-weight: 400;\">Top 30+ Most Asked Front-end Developer Interview Questions For 2024<\/span><\/a><\/li><li style=\"font-weight: 400;\" aria-level=\"1\"><a href=\"https:\/\/www.w3webschool.com\/blog\/graphic-design-interview-questions\/\"><span style=\"font-weight: 400;\">Top 30+ Graphic Design Interview Questions For 2024 [With Answers]<\/span><\/a><\/li><li style=\"font-weight: 400;\" aria-level=\"1\"><a href=\"https:\/\/www.w3webschool.com\/blog\/java-developer-interview-questions-and-answers\/\"><span style=\"font-weight: 400;\">Trending 25+ Web Developer Interview Questions &amp; Answers for 2024<\/span><\/a><\/li><\/ul><p><span style=\"font-weight: 400;\">Happy Reading!<\/span><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t<div class=\"elementor-column elementor-col-33 elementor-inner-column elementor-element elementor-element-bde134e elementor-hidden-tablet elementor-hidden-mobile\" data-id=\"bde134e\" data-element_type=\"column\" data-e-type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-54a27b2 elementor-align-justify elementor-widget elementor-widget-button\" data-id=\"54a27b2\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"button.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<div class=\"elementor-button-wrapper\">\n\t\t\t\t\t<a class=\"elementor-button elementor-button-link elementor-size-sm\" href=\"https:\/\/www.w3webschool.com\/full-stack-web-development-course-in-kolkata\/\" target=\"_blank\">\n\t\t\t\t\t\t<span class=\"elementor-button-content-wrapper\">\n\t\t\t\t\t\t\t\t\t<span class=\"elementor-button-text\">Join Crash Course Today<\/span>\n\t\t\t\t\t<\/span>\n\t\t\t\t\t<\/a>\n\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<\/div>\n\t\t","protected":false},"excerpt":{"rendered":"<p>Home Most-asked 15+ JavaScript Interview Questions and Answers [2025 Updated] Table of Contents Are you brushing yourself for a JavaScript interview in 2025? It can be a little bit challenging as there are a huge amount of concepts to learn and remember! Are you feeling nervous about how many topics you have to brush up &#8230; <a title=\"Most-asked 15+ JavaScript Interview Questions and Answers [2025 Updated]\" class=\"read-more\" href=\"https:\/\/www.w3webschool.com\/blog\/javascript-interview-questions\/\" aria-label=\"Read more about Most-asked 15+ JavaScript Interview Questions and Answers [2025 Updated]\">Read more<\/a><\/p>\n","protected":false},"author":1,"featured_media":15863,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"elementor_header_footer","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-15835","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-seo"],"_links":{"self":[{"href":"https:\/\/www.w3webschool.com\/blog\/wp-json\/wp\/v2\/posts\/15835"}],"collection":[{"href":"https:\/\/www.w3webschool.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.w3webschool.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.w3webschool.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.w3webschool.com\/blog\/wp-json\/wp\/v2\/comments?post=15835"}],"version-history":[{"count":0,"href":"https:\/\/www.w3webschool.com\/blog\/wp-json\/wp\/v2\/posts\/15835\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.w3webschool.com\/blog\/wp-json\/wp\/v2\/media\/15863"}],"wp:attachment":[{"href":"https:\/\/www.w3webschool.com\/blog\/wp-json\/wp\/v2\/media?parent=15835"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.w3webschool.com\/blog\/wp-json\/wp\/v2\/categories?post=15835"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.w3webschool.com\/blog\/wp-json\/wp\/v2\/tags?post=15835"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}