Are you a fresher looking for some interview questions to ask during your next job interview? If so, you’re in luck. In this article, we will provide you with basic javascript interview questions that will test your skills and knowledge.
JavaScript Interview Questions for Freshers
1. What is Javascript?
Javascript is a computer programming language that is most commonly used for developing websites. It is a scripting language, which means that it can be embedded into HTML web pages for applications such as automatic checking for and filling of forms, pop-up windows etc.
2. What are the Basic Syntaxes of Javascript?
Javascript is a basic object-oriented programming language for the web browser. It is used to develop interactive web pages. Thus, the syntax is not very different from other object-oriented programming languages. The basic syntax of Javascript includes the following:
- var keyword: This declares a variable.
- let keyword: This declares a local variable.
- function keyword: This defines a function.
- class keyword: This defines a class.
- var statement: This assigns a value to the variable declared earlier in the code block.
- let statement: This assigns the value of an expression to the local variable declared earlier in the code block.
- function statement: This calls the function defined earlier in the code block with one or more arguments.
- class statement: This creates an instance of the class defined
3: How to Declare Variables in Javascript?
A variable is a named storage location that holds data. The data can be a number, a word, or a sentence. Data can change during the course of a program. Declaring a variable in Javascript is as simple as giving it a name and initializing it with a value.
In JavaScript, there are 2 ways to declare variables. One is var declaration, which is used to declare only a single global variable. The other islet declaration is used to declare a block scope variable.
For example, let a = 5 var b = 6 means b cannot be accessed outside of the block scope. However, let a = 5 var b = 6 means b can be accessed outside of the block scope.
var HelloWorld = "Hello World!";
The above code declares a string variable and assigns the value “Hello World!” to it.
var number = 2;
The above code declares a number variable and assigns the value “2” to it.
var name = true;
The above code declares a boolean variable and assigns the boolean value “true” to it.
4: How to Write Simple Functions in Javascript?
In javascript, functions are a way to group code into a set of instructions that can be executed repeatedly. They are frequently used to support code reuse and other programming patterns. There are different kinds of functions in javascript, including regular, anonymous and named functions. Here is the simplest way to create a simple function in javascript.
function printHello() {
console.log("Hello World!");
}The above code will print “Hello World!” on the console every time it is executed.
5. How to Use Functions in JavaScript?
Functions are a fundamental part of programming, and they allow you to modularize your code and make it more organized. When you write a function, you should always start by writing the simplest possible code, and then adding additional functionality as needed. Here are some tips for using functions in javascript:
1. Always return a value:
when you write a function, always return a value (either an expression or an object). This will make your code easier to read and debug, and it will also help you avoid errors.
2. Pass in the correct arguments:
when you call a function, always pass in the correct arguments (in order), and don’t forget to include the parentheses. This will ensure that your function works as expected, and it will also make your code easier to read.
3. Keep your code simple:
when you write code, always try to keep it as simple as possible. This will make it easier to understand and debug, and it will also make your code faster to execute.
4. Use variables sparingly:
when you write code, use variables sparingly (if at all). This will make your code more readable and maintain
6: What are the Different Types of Data Structures in Javascript?
Data structures are the heart of designing computer programs. It has two main parts: data and operations. In computer science, the data structure is defined as a particular model of representing and organizing data in a computer so that it can be used efficiently to solve problems. There are many different data structures available in JavaScript, and they are classified into two types:
1. Linear Data Structures:
these are structures that allow you to store data in a sequence, and the operations that you can perform on them are all linear (e.g. adding two numbers is always the same).
2. Arrays:
these are structures that allow you to store data in a contiguous location, and the operations that you can perform on them are all linear (e.g. adding two numbers is always the same).
7: What are the Different Ways to Implement Search Engines in Javascript?
There are a few different ways that you can implement search engines in javascript:
- using the built-in search functionality of jsDOM: jsDOM provides a convenient way to access the DOM and perform searches through it.
- using the Yahoo! JQuery Search Plugin: This plugin provides a convenient way to add search functionality to your web applications.
- using the Google AJAX Search API: This API allows you to access the search functionality of Google’s web services directly from your javascript code.
Javascript Interview Questions Advanced Topics You Should Prepare for?
There are a few advanced topics that you should know about when working with javascript:
1. Closures:
Closures are a powerful feature of javascript that allows you to hide the details of certain code blocks from other parts of your program. This can make your code more modular and easier to understand.
2. Callbacks:
Callbacks are another powerful feature of javascript that allows you to execute code after specific events have occurred. This can be useful for performing complex tasks in response to user input, or for triggering automatic actions in your program.
3. Prototypes:
Prototypes are a special type of object in javascript that allows you to access the properties and methods of objects that have been created by other parts
Conclusion
This blog post is for the Javascript developers who are starting their careers or even freshers who are going to join a company as a developer and are preparing for the interviews. Here we have shared with 10 most important JavaScript Interview Questions which should be answered by the candidates. Hope this blog helps you all!
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