Top 100 JavaScript Interview Questions and Answers

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[ahmed_raaphat]

🇵🇸 TIMESTAMPS: 🇵🇸

02:14 what is Javascript? what is the role of JS engine?
05:00 What are Client side and Server side?
06:30 What is Scope in JS?
09:48 What is Hoisting in Javascript?
11:49 What is JSON?

13:18 What are variables? var vs let vs const.
16:50 What are data types in JS?
18:15 what is the difference between primitive and non-primitive data types?
22:23 what is the difference between null and undefined in JS?
25:12 what is the use of typeof operator?
26:28 what is type coercion in JS?

28:43 what is operator precedence?
29:37 Unary vs Binary vs Ternary operators.
31:10 What is short-circuit evaluation in JS?
34:22 Conditional Statement Types.
41:01 Double equals == vs === Triple equals
42:49 Spread operator and Rest operator in JS

47:00 what are arrays in JS? How to insert, remove, access, sort, reverse and manipulate array elements?
01:05:34 what is Array Destructing in JS?
01:07:12 what are array-like objects in JS?
01:10:05 How to convert an array-like object into an array?

01:12:05 what are loops? what are the types of loops in JS?
01:19:10 what is the difference between for and for..of loops in JS?
01:20:40 what is the difference between for..of and for..in loops in JS?
01:22:10 what is forEach loop? Compare it with the above methods.

01:27:03 what are Functions in JS? what are the types of functions?
01:38:27 what is the difference between arguments and parameters?
01:40:54 Default Parameters in functions in JS.
01:41:50 what is the use of event handling in JS?
01:44:30 what are First-Class functions in JS?
01:44:55 what are Pure and Impure functions in JS?
01:48:53 what is Function Currying in JS?
01:51:27 call() & apply() & bind() methods in JS?

01:54:22 what is a string?
01:54:43 Template Literals and String Interpolation
01:56:15 single quotes vs double quotes vs backticks
01:56:52 String Operations in JS
01:59:01 what is string immutability?
02:00:37 Different ways to concatenate strings in JS

02:02:20 what is DOM? what is the difference between HTML and DOM?
02:04:55 How do you select, modify, or remove DOM elements?
02:05:53 Selectors in JS DOM.
02:10:47 what are the methods to manipulate elements, properties and attributes of JS DOM?
02:11:26 what is the difference between innerHTML vs textContent?
02:12:50 How to add or remove properties of HTML elements from the DOM using JS?
02:13:59 How to add or remove style of HTML elements in the DOM using JS?
02:14:55 How to create new elements in DOM using JS?

02:18:21 Error Handling in JS
02:22:56 what is Error Propagation in JS?
02:23:35 Error Handling Best Practices
02:24:37 what are the different types of error in JS?

02:26:25 what are objects in JS?
02:30:05 what is the difference between an array and an object?
02:31:00 How to manipulate Objects in JS?
02:31:37 Dot Notation vs Bracket Notation
02:33:00 How to iterate through Objects in JS?
02:34:34 How to check if a property exists or not?
02:36:00 How to clone an object?
02:40:33 Sets in JS
2:42:59 Map Object in JS

2:45:40 Events in JS
2:50:47 Event Delegation in JS
2:52:50 Event Bubbling and Event Capturing in JS
method in JS
2:58:28 The use of "this" keyword in the context of event handling in JS
2:59:00 How to remove (unattach) an event handler from an element in JS

[SSRathore]

This is not just a interview question video, but the whole documentation of JavaScript in compressed form, and really far better than those coding tutorials of 10 to 15 hours.

Animations, presentation and using code examples and no garbage talking, point to point things make it seems like a paid course. You can jump to Node js or React after watching this easily

Thanks a lot Sir

[fazilhakkim]

one of the great video I have seen ..thanks for your teaching

[kuldeepdawar]

Thanks for this video Brother, your explanation is very clear and wisely. You are helping a lot by this content thanks.. I am looking React videos like that explanation..🙂

[harshthosar]

9:00 I have always had this question in my mind. No interviewer had asked me this, but I always had this doubt. Thank you, sir, for covering everything with such details.

[malarvizhit]

Thank you for teaching sir, it was a wonderful video and i feel confident.

[engineersINnight]

Hello Happy Ji. Your interviews Questions are more helped me to get 2 Offers Letters with Salary Hike. Please keep it on. These videos will help more persons like me. also Please create a 100 FAQs on jQueries too.

[smartygaming]

Nice sir it's mostly all are the interview questions are covered, and as a fresher it's very very useful for me for the interview. Sir I support you and also make more videos on other technology like Node.js MySQL, Java it up....👍👍

[ekarthika]

Sir after three years i have a confident for attend the interview. I bought your 500 interview questions and prepare one week now I feel I'm expert in. Net

[aniketshahane]

For my reference :
12:39 Chapter 2 : Variables & Datatypes
28:12 Chapter 3 : Operators & Conditions
46:16 Chapter 4 : Arrays
1:11:39 Chapter 5 : Loops
1:26:25 Chapter 6 : Functions
1:56:01 Chapter 7 : Strings
2:01:55 Chapter 8 : DOM
2:18:22 Chapter 9 : Error Handling
2:25:57 Chapter 10 : Objects
2:45:28 Chapter 11 : Events

[kalyanbellamkonda]

Sir very good session great sir thank you Love from Andhrapradesh

[dilipkumarmattewada]

Good explanation covered all topics..
Please make one video for python - experienced

[ameeradda]

@Bro... You are really awesome. You also made things very easy to understand; your explanation and graphics are very informative. Good Job.

[deepakprajapati]

app kitna simplyfy krke concepts smjate ho ajj tak esa video ni dekha youtube par you are osm teacher prnam guruji dhanyvad for this

[MeetPatel-zlei]

Everything you covered sir except promises and async/await ❤

[Leen-Odeh]

best JS interview questions tutorial, Thank You!

[priyankakhairnarborse]

Finally completed the whole video feeling confident and thank you so much sir for this the explanation was amazing.

[UsmanKhalid]

Watching your video for the first time. Believe me, it is one of the best tutorial available for me. Even paid courses are not that much clear. You got your self a new subscriber. Respect from Pakistan.

[srikarravoori]

I have completed one hour and will complete the remaining soon. Really its simple and easy to understand. The video is prepared with utmost care interms of presentation. For the interview candidates, its one stop to cover all js questions.Thank you.

[rahulsharma]

Thank you so much Happy Sir, I learnt a lot from this course, Got placed in two companies. Thank you