Most Asked JavaScript Interview Questions 2024

By Team foundit July 17, 2024

[{"selector":"#anim-c81b6ed4-38e7-4891-826e-63436b213337","keyframes":{"opacity":[1,1]},"delay":10,"duration":1500,"easing":"cubic-bezier(.3,0,.55,1)","fill":"both"}] [{"selector":"#anim-65812537-aac0-4487-84c5-539cbcc430ca","keyframes":{"transform":["scale(3)","scale(1)"]},"delay":10,"duration":1500,"easing":"cubic-bezier(.3,0,.55,1)","fill":"forwards"}] [{"selector":"#anim-79cd599d-10c9-4c14-9503-f54854afe67e","keyframes":{"opacity":[0,1]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"both"}] [{"selector":"#anim-8c2fc2e7-f791-4d2d-989e-59ff05f5b61a","keyframes":{"transform":["scale(0.3333333333333333)","scale(1)"]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"forwards"}] Feeling unprepared for Javascript interviews? Master these common JavaScript interview questions.

What are Data Types?

[{"selector":"#anim-71426232-548d-4a4d-a9de-7a0d9e1caa42","keyframes":{"opacity":[1,1]},"delay":10,"duration":1500,"easing":"cubic-bezier(.3,0,.55,1)","fill":"both"}] [{"selector":"#anim-2a1e5343-7742-441f-a9b4-1a38ff5c4520","keyframes":{"transform":["scale(3)","scale(1)"]},"delay":10,"duration":1500,"easing":"cubic-bezier(.3,0,.55,1)","fill":"forwards"}] [{"selector":"#anim-1b32906c-ab33-4797-a4f1-e6f4f1b6259a","keyframes":{"opacity":[0,1]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"both"}] [{"selector":"#anim-7bf48813-688c-40ae-be83-be8b4a83f31c","keyframes":{"transform":["scale(0.3333333333333333)","scale(1)"]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"forwards"}] [{"selector":"#anim-7b01840c-9010-44dd-bda4-fd1414d70846","keyframes":{"opacity":[0,1]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"both"}] [{"selector":"#anim-69621433-1c44-4d01-8764-690aea9225b0","keyframes":{"transform":["scale(0.3333333333333333)","scale(1)"]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"forwards"}] Can you explain different data types in Javascript (strings, numbers, etc.)?

Functions 101

[{"selector":"#anim-1450ab02-0be8-49ff-8d73-c2e3bafc08a1","keyframes":{"opacity":[1,1]},"delay":10,"duration":1500,"easing":"cubic-bezier(.3,0,.55,1)","fill":"both"}] [{"selector":"#anim-c40afa2c-cd1f-48c8-9c8d-6180e04ef131","keyframes":{"transform":["scale(3)","scale(1)"]},"delay":10,"duration":1500,"easing":"cubic-bezier(.3,0,.55,1)","fill":"forwards"}] [{"selector":"#anim-68dd0a55-9a7d-46c3-8a2a-fabadb6414ec","keyframes":{"opacity":[0,1]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"both"}] [{"selector":"#anim-e89b5c33-11a4-49d6-b3bf-913b5c05abd2","keyframes":{"transform":["scale(0.3333333333333333)","scale(1)"]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"forwards"}] [{"selector":"#anim-a27750c8-f78a-415b-8659-10715d0a7a7d","keyframes":{"opacity":[0,1]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"both"}] [{"selector":"#anim-d9836914-9abb-4ce9-9806-0a73c33a8bb2","keyframes":{"transform":["scale(0.3333333333333333)","scale(1)"]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"forwards"}] How do you define and call a function in Javascript?

Loops & Decisions

[{"selector":"#anim-276576f5-5f99-4c6e-8016-c67c25bda5f2","keyframes":{"opacity":[1,1]},"delay":10,"duration":1500,"easing":"cubic-bezier(.3,0,.55,1)","fill":"both"}] [{"selector":"#anim-c41743cc-e149-4d6f-9166-81dd0116a46f","keyframes":{"transform":["scale(3)","scale(1)"]},"delay":10,"duration":1500,"easing":"cubic-bezier(.3,0,.55,1)","fill":"forwards"}] [{"selector":"#anim-6baea6af-92ed-44c4-923f-254d2cb7dd77","keyframes":{"opacity":[0,1]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"both"}] [{"selector":"#anim-554d2a61-ae09-486a-8487-8ea6049dc12d","keyframes":{"transform":["scale(0.3333333333333333)","scale(1)"]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"forwards"}] [{"selector":"#anim-262795f4-e42b-487d-aa95-e2bf9d345bc5","keyframes":{"opacity":[0,1]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"both"}] [{"selector":"#anim-fbc96405-4cd3-43e4-9624-8576577e8c55","keyframes":{"transform":["scale(0.3333333333333333)","scale(1)"]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"forwards"}] Explain the use of for loops, while loops, and conditional statements (if/else).

DOM Manipulation

[{"selector":"#anim-dc2322fd-73e1-49c2-91bc-75dbdabb9b8f","keyframes":{"opacity":[1,1]},"delay":10,"duration":1500,"easing":"cubic-bezier(.3,0,.55,1)","fill":"both"}] [{"selector":"#anim-56b07f56-a0cf-4d55-b4a0-b2d6aab0cb3a","keyframes":{"transform":["scale(3)","scale(1)"]},"delay":10,"duration":1500,"easing":"cubic-bezier(.3,0,.55,1)","fill":"forwards"}] [{"selector":"#anim-8336d0dc-ffff-4bd2-8cbc-71477dda19a0","keyframes":{"opacity":[0,1]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"both"}] [{"selector":"#anim-ae73766f-8791-4d39-bf80-b52a81734ef7","keyframes":{"transform":["scale(0.3333333333333333)","scale(1)"]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"forwards"}] [{"selector":"#anim-a84760f4-f2ee-4045-ab79-35c0edf9f97d","keyframes":{"opacity":[0,1]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"both"}] [{"selector":"#anim-24969e4d-cf75-4084-bb91-14ef9fcba009","keyframes":{"transform":["scale(0.3333333333333333)","scale(1)"]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"forwards"}] How do you access and modify elements in the Document Object Model (DOM)?

Arrays & Objects

[{"selector":"#anim-c544b0d1-230a-48dd-a59f-44c239bc6273","keyframes":{"opacity":[1,1]},"delay":10,"duration":1500,"easing":"cubic-bezier(.3,0,.55,1)","fill":"both"}] [{"selector":"#anim-a46fae87-20e5-4fb4-afd6-0645a88cb448","keyframes":{"transform":["scale(3)","scale(1)"]},"delay":10,"duration":1500,"easing":"cubic-bezier(.3,0,.55,1)","fill":"forwards"}] [{"selector":"#anim-c6ce3cdd-5098-4077-925b-f81ac9f81834","keyframes":{"opacity":[0,1]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"both"}] [{"selector":"#anim-203ffc09-4715-4a00-805a-a703d47af037","keyframes":{"transform":["scale(0.3333333333333333)","scale(1)"]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"forwards"}] [{"selector":"#anim-52ab54ab-9991-4165-a563-b745008f6020","keyframes":{"opacity":[0,1]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"both"}] [{"selector":"#anim-83302892-dd13-4c72-a80e-2c9ed4f1e946","keyframes":{"transform":["scale(0.3333333333333333)","scale(1)"]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"forwards"}] What's the difference between arrays and objects in Javascript?

This Keyword

[{"selector":"#anim-e6ebdb02-9395-41f0-b2ec-5b1db5a23f2c","keyframes":{"opacity":[1,1]},"delay":10,"duration":1500,"easing":"cubic-bezier(.3,0,.55,1)","fill":"both"}] [{"selector":"#anim-992d6113-f783-44c3-8fdb-d7d6876ca8a3","keyframes":{"transform":["scale(3)","scale(1)"]},"delay":10,"duration":1500,"easing":"cubic-bezier(.3,0,.55,1)","fill":"forwards"}] [{"selector":"#anim-8f22e211-f1b5-4837-b49b-a8dcd27b961b","keyframes":{"opacity":[0,1]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"both"}] [{"selector":"#anim-741fdcbd-aa4e-4c18-9803-fc0a709908d9","keyframes":{"transform":["scale(0.3333333333333333)","scale(1)"]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"forwards"}] [{"selector":"#anim-c6fbff35-6791-4243-aa4a-b7e4c2641ddb","keyframes":{"opacity":[0,1]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"both"}] [{"selector":"#anim-f77ac752-04f0-4386-b8ab-dabd9040ef92","keyframes":{"transform":["scale(0.3333333333333333)","scale(1)"]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"forwards"}] Explain the concept of the 'this' keyword in Javascript and how it works.

Event Listeners

[{"selector":"#anim-5ba6f9bf-9cbd-464e-be58-4b15453322c2","keyframes":{"opacity":[1,1]},"delay":10,"duration":1500,"easing":"cubic-bezier(.3,0,.55,1)","fill":"both"}] [{"selector":"#anim-9364ea23-4763-4d02-b2c8-39235c398e75","keyframes":{"transform":["scale(3)","scale(1)"]},"delay":10,"duration":1500,"easing":"cubic-bezier(.3,0,.55,1)","fill":"forwards"}] [{"selector":"#anim-8a48780b-6560-4ee8-9b38-35872036e8f8","keyframes":{"opacity":[0,1]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"both"}] [{"selector":"#anim-1144a6cd-96dd-469e-91e5-6c349f714b5e","keyframes":{"transform":["scale(0.3333333333333333)","scale(1)"]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"forwards"}] [{"selector":"#anim-f8042500-7f2f-41ef-b3cf-5a4025035299","keyframes":{"opacity":[0,1]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"both"}] [{"selector":"#anim-4ee5346e-3f78-4f6e-b780-6aef8a6e5134","keyframes":{"transform":["scale(0.3333333333333333)","scale(1)"]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"forwards"}] How do you attach event listeners to elements in Javascript (clicks, scrolls, etc.)?

Error Handling

[{"selector":"#anim-3c859298-15f1-42ac-9abf-ae56b8b0ac18","keyframes":{"opacity":[1,1]},"delay":10,"duration":1500,"easing":"cubic-bezier(.3,0,.55,1)","fill":"both"}] [{"selector":"#anim-16ac144d-7e1d-4dc8-ba71-caf87da8a1c2","keyframes":{"transform":["scale(3)","scale(1)"]},"delay":10,"duration":1500,"easing":"cubic-bezier(.3,0,.55,1)","fill":"forwards"}] [{"selector":"#anim-7f4e55dc-a816-4c81-87a1-97a768161d19","keyframes":{"opacity":[0,1]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"both"}] [{"selector":"#anim-9b5360c2-435b-442b-830a-b0b4dea1624f","keyframes":{"transform":["scale(0.3333333333333333)","scale(1)"]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"forwards"}] [{"selector":"#anim-b2947ec9-72cf-4d28-8ef0-286a3cee383a","keyframes":{"opacity":[0,1]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"both"}] [{"selector":"#anim-e59cdc24-0b50-4dc9-8031-6942257428b8","keyframes":{"transform":["scale(0.3333333333333333)","scale(1)"]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"forwards"}] How do you handle errors in Javascript using try...catch blocks?

Asynchronous JS

[{"selector":"#anim-b1b55d62-f0c7-492a-95d2-63607706f5eb","keyframes":{"opacity":[1,1]},"delay":10,"duration":1500,"easing":"cubic-bezier(.3,0,.55,1)","fill":"both"}] [{"selector":"#anim-ab6b6d57-f1f9-45eb-8225-b9705629733c","keyframes":{"transform":["scale(3)","scale(1)"]},"delay":10,"duration":1500,"easing":"cubic-bezier(.3,0,.55,1)","fill":"forwards"}] [{"selector":"#anim-1b52155f-c79b-4aba-bcd3-c330c9ae4bd0","keyframes":{"opacity":[0,1]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"both"}] [{"selector":"#anim-74bc4f43-eec5-47a0-8681-7bab426614b1","keyframes":{"transform":["scale(0.3333333333333333)","scale(1)"]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"forwards"}] [{"selector":"#anim-d7397c34-dc2d-4a20-899a-acc48072ab27","keyframes":{"opacity":[0,1]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"both"}] [{"selector":"#anim-04f8e0aa-24bc-438b-b380-dc2718a5bd96","keyframes":{"transform":["scale(0.3333333333333333)","scale(1)"]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"forwards"}] Explain the concept of asynchronous programming and callbacks in Javascript.

Ready To Apply

[{"selector":"#anim-2235ae22-3cbf-4200-bea9-4f76968ce3ee","keyframes":{"opacity":[1,1]},"delay":10,"duration":1500,"easing":"cubic-bezier(.3,0,.55,1)","fill":"both"}] [{"selector":"#anim-ab2146ca-0149-40ad-b0b6-42c4a4cb4820","keyframes":{"transform":["scale(3)","scale(1)"]},"delay":10,"duration":1500,"easing":"cubic-bezier(.3,0,.55,1)","fill":"forwards"}] [{"selector":"#anim-74d5d6c4-8e8a-4fc6-b5d9-4ee7a75546f2","keyframes":{"opacity":[0,1]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"both"}] [{"selector":"#anim-0832a79f-f5fd-4526-a589-a654f8d4b278","keyframes":{"transform":["scale(0.3333333333333333)","scale(1)"]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"forwards"}] [{"selector":"#anim-61527ec7-78dd-49dd-90ba-91aaf56757db","keyframes":{"opacity":[0,1]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"both"}] [{"selector":"#anim-b6195195-b5f6-4fb8-a514-8d47607cf8f1","keyframes":{"transform":["scale(0.3333333333333333)","scale(1)"]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"forwards"}] Don't wait! Update your resume and register at foundit to apply for JavaScript Developer job opportunities. Register Now