The evolution of web-based technologies has contributed to the development of programming languages, and one of them is JavaScript. In the market, many frameworks are based on JavaScript. Are you planning your career in the IT and software industry? Want to become a front-end web developer or JavaScript developer? Are you searching for the best JavaScript developer jobs? If yes, you’ll need to crack the JavaScript interview with your knowledge.
Every interview is different, so you need to be prepared well for it. Here are the top Javascript interview questions and answers that will help you succeed in your interview.
Let’s check them out in a detailed manner-
Q. What’s the difference between JavaScript and Java?
A. The main difference between JavaScript and Java are-
JavaScript
- JavaScript is mainly an object-oriented scripting language.
- JavaScript does not require compilation before running the application code.
- JavaScript applications help to run inside a web browser.
Java
- Java is mainly an object-oriented programming language.
- Java source code requires a compiler before it can be ready to run in real-time.
- Java applications are best to be used in operating systems and virtual machines.
Q. What are the benefits of JavaScript over other technologies?
A. These are numerous advantages of JavaScript that are mentioned below-
- Rich User Interface
JavaScript is featured with a rich user interface that helps make the UI of web applications look better.
- Frameworks
Another crucial advantage is its numerous frameworks. JavaScript has countless frameworks and libraries that can be used for developing games and web applications of all kinds.
- Enhanced Interaction
JavaScript can add interaction to the static web pages and make them react to users’ inputs.
- Quick Feedback
If running is JavaScript, there is no need for a web page to reload.
Q. What sort of disadvantages are of using inner HTML in JavaScript?
A. If you’re using inner HTML in JavaScript, then these are the disadvantages that one can face:
- If there’s age-old content, then it can be easily replaced.
- Appends to inner HTML won’t be able to be used.
- The application of inner HTML is much slower when compared to the rest of the variables.
- The inner HTML content is slowly built and is further divided into different elects that take time to get re-parsed.
- If using inner HTML, the content will get replaced in JavaScript
- The use of inner HTML can break the document of JavaScript.
Q. Can You name and identify the basic data types of JavaScript?
A. JavaScript is of 7 basic data types that a developer needs to know. These are
Null which represents unknown values, empty, or nothing
The string is for the combination of any alphanumeric values
Boolean returns true or false
The symbol is to create unique identifiers for objects
The number is used for integers and floating-point values
Undefined means whose value is not assigned
The object can be used to store data or other complex entities
Q. What are the scopes of a variable in JavaScript?
This is one of the common questions asked in the javascript developer jobs interview. The scope of a variable means the variable that has been defined or declared in a JavaScript program. Mainly, there are two scopes of a variable that includes-
- Local Scope: Local variables are accessible only within a defined function.
- Global Scope: Global variables with global scope can be found everywhere in JavaScript code.
Q. What are screen objects, and can you define their properties?
A. Screen objects in JavaScript are used to read different types of information from a client screen. Some of the properties of screen objects are as follows:
- A width of the screen is given.
- The height of the client screen will include the taskbar and screen objects
- The height of the screen is given.
- The width of the screen includes the taskbar and the overall width
- Images on the client screen are also provided.
Q. How would a JavaScript developer delete a cookie?
A. Deletion of a cookie in JavaScript can be done by setting an expiration date and time. Make sure to specify the correct path of the cookie that needs to be deleted, as some browsers won’t allow the deletion of cookies unless there is a clear path. This will tell which cookie to delete from the user’s machine.
Q. Can you name the ways of defining a variable in JavaScript?
A. Mainly, there are three ways of defining a variable in JavaScript, and these are as follows-
Const: This can be used to declare/define a variable, but the value is constant throughout the JavaScript program. So, it cannot be modified at a later time.
Let: This tells that the values can be changed within the JavaScript code at a later time.
Var: Var is mainly used to declare a variable, and then this value can be changed within the JavaScript code at a later time.
Q. What is the difference between AngularJS and JavaScript?
A. AngularJS
- This is a framework mainly used for both web and mobile-based applications.
- AngularJS supports iterations or any other conditional constructs.
- In AngularJS, filters are supported
- AngularJS is built by using JavaScript.
JavaScript
- JavaScript is a programming language.
- JavaScript supports programming paradigms, including exceptions, conditional statements, iterations, etc.
- In JavaScript, filters are not supported.
- It is used in building frameworks.
To sum up
There’s a great demand for javascript developer jobs in software and IT. Those who aspire to have a career in this field need to be well-prepared for the interview. The interview mentioned above questions are specially prepared to help you do well in your interviews and selection process.
