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- What are the different data types present in javascript? To know the type of a JavaScript variable, we can use the typeof operator. 1. Primitive types.
- Explain Hoisting in javascript. Hoisting is the default behaviour of javascript where all the variable and function declarations are moved on top. This means that irrespective of where the variables and functions are declared, they are moved on top of the scope.
- Why do we use the word “debugger” in javascript? The debugger for the browser must be activated in order to debug the code. Built-in debuggers may be switched on and off, requiring the user to report faults.
- Difference between “ == “ and “ === “ operators. Both are comparison operators. The difference between both the operators is that “==” is used to compare values whereas, “ === “ is used to compare both values and types.
- What is JavaScript? A high-level, interpreted programming language called JavaScript makes it possible to create interactive web pages and online apps with dynamic functionality.
- What are the different data types in JavaScript? JavaScript has six primitive data types: Number. String. Boolean. Null. Undefined. Symbol. It also has two compound data types
- What is hoisting in JavaScript? Hoisting is a JavaScript concept that refers to the process of moving declarations to the top of their scope. This means that variables and functions can be used before they are declared, as long as they are declared before they are used in a function.
- What is the difference between null and undefined? null is an assignment value that represents no value or an empty value, while undefined is a variable that has been declared but not assigned a value.
- Javascript Interview Questions For Freshers
- Javascript Intermediate Interview Questions
- Javascript Interview Questions For Experienced
Let’s discuss some common questions that you should prepare for the interviews. These questions will be helpful in clearing the interviews specially for the frontend development role.
21. What are all the looping structures in JavaScript?
1. while loop:A while loop is a control flow statement that allows code to be executed repeatedly based on a given Boolean condition. The while loop can be thought of as a repeating if statement. 2. for loop:A for loop provides a concise way of writing the loop structure. Unlike a while loop, for statement consumes the initialization, condition and increment/decrement in one line thereby providing a shorter, easy to debug structure of looping. 3. do while:A do-while loop is similar to while l...
22. How can the style/class of an element be changed?
To change the style/class of an element there are two possible ways. We use document.getElementByID method
23. Explain how to read and write a file using JavaScript?
1. The readFile()functions is used for reading operation. 1. The writeFile()functions is used for writing operation.
31. What is the ‘Strict’ mode in JavaScript and how can it be enabled?
Strict Mode is a new feature in ECMAScript 5 that allows you to place a program or a function in a “strict” operating context. This strict context prevents certain actions from being taken and throws more exceptions. The statement “use strict” instructs the browser to use the Strict mode, which is a reduced and safer feature set of JavaScript.
32. How to get the status of a CheckBox?
The DOM Input Checkbox Property is used to set or return the checked status of a checkbox field. This property is used to reflect the HTML Checked attribute. If the CheckBox is checked then it returns True.
33. How to explain closures in JavaScript and when to use it?
The closure is created when a child functions to keep the environment of the parent’s scope even after the parent’s function has already executed. The Closure is a locally declared variable related to a function. The closure will provide better control over the code when using them.
This question tests your understanding of type coercion in JavaScript, a concept that can lead to subtle bugs if not properly understood. Answer: == (abstract equality) compares values after type coercion. === (strict equality) checks both value and type without type coercion. Example: 1=='1';// true1==='1';// false. 5.
- Jacinto Wong
- What is JavaScript? What are some of its core ‘stand-out’ features? JavaScript (also commonly known as JS), is a high-level programming language that is used to create interactive elements on the web.
- What is the difference between let and var? In JavaScript, both let and var are used to declare variables, but they have some key differences in how they are scoped.
- What is the difference between null and undefined? In JS, null and undefined are both used to represent the absence of a value, but they have different meanings.
- What is an example of an asynchronous function? setTimeout is a great example of an asynchronous function in JavaScript. It’s used to delay the execution of a piece of code by a specified amount of time, and is often used to simulate a long-running operation, such as a network request.
Apr 17, 2024 · Interview Preparation. 65 JavaScript Interview Questions & Answers to Prepare For (Beg to Adv) 2024-04-1741 min readWritten by William Juan. Written byWilliam Juan. Summary: Practice common basic, intermediate, and advanced JavaScript interview questions and answers with this comprehensive guide. Good luck!
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4 days ago · In this article, we’ve compiled the top 10 JavaScript interview questions that you’re likely to encounter in your technical interview, along with hints, explanations, and code examples. By mastering these concepts, you’ll walk into your next interview with more confidence, ready to tackle most challenges thrown your way.
