8 Must-Know Technical Interview Questions and Sample Answers

  Here are the 8 technical interview questions that are commonly asked in web developer interviews along with sample answers:

1. What is the difference between null and undefined in JavaScript?
   null is an assignment value that represents no value or no object. It is a primitive value. On the other hand, undefined means that a variable has been declared but has not been assigned a value yet. It is also a primitive value. In short, null is an intentional absence of any object value, while undefined represents an uninitialized or missing value.

2. What is the purpose of CSS media queries?
   CSS media queries allow you to apply different styles based on various device characteristics such as screen size, resolution, orientation, etc. They enable you to create responsive designs that adapt to different devices and screen sizes.

3. What is the difference between == and === in JavaScript?
   The double equals (==) operator performs type coercion if the operands are of different types before making the comparison. On the other hand, the triple equals (===) operator does not perform type coercion and checks for both value and type equality.

4. What is the box model in CSS?
   The box model in CSS describes how elements are rendered on a web page. It consists of four components: content, padding, border, and margin. The content area contains the actual content of the element, while padding provides space between the content and the border. The border surrounds the padding and content, and margin creates space between elements.

5. What are some ways to optimize website performance?
   Some ways to optimize website performance include minimizing HTTP requests, compressing files (e.g., using GZIP), leveraging browser caching, optimizing images, minifying CSS and JavaScript files, using a content delivery network (CDN), and reducing server response time.

6. What is the difference between let, const, and var in JavaScript?
   let and const are block-scoped variables introduced in ES6 (ECMAScript 2015). They have block-level scope and cannot be redeclared within the same scope. On the other hand, var is function-scoped and can be redeclared within the same scope.

7. What is responsive web design?
   Responsive web design is an approach to web design that aims to make web pages render well on a variety of devices and window or screen sizes. It involves using flexible layouts, fluid grids, and media queries to create designs that adapt to different devices.

8. What are some common HTTP status codes?
   Some common HTTP status codes include:

   • 200 OK: The request was successful.
   • 404 Not Found: The requested resource could not be found.
   • 500 Internal Server Error: A generic server error occurred.
   • 301 Moved Permanently: The requested resource has been permanently moved to a new location.

Remember that these questions are just a starting point for your preparation. It’s essential to understand the concepts behind them and be able to explain your thought process during an interview.

Good luck with your interview preparation! 🍀