These questions cover a broad range of web development topics and are often asked during interviews to assess a candidate’s technical knowledge and problem-solving skills. It’s important to be familiar with these concepts and be able to explain them clearly and concisely.
Here we listed top 20 web development interview questions with answers.
What is the difference between HTML and XHTML?
HTML (Hypertext Markup Language) and XHTML (Extensible Hypertext Markup Language) are two different versions of markup languages used to create web pages.
The main differences between HTML and XHTML are:
Syntax: XHTML has a stricter syntax compared to HTML, which means that it requires a well-formed XML structure. HTML, on the other hand, has a more lenient syntax and is more forgiving of errors.
Tagging: XHTML requires all tags to be closed, while HTML has some tags that can be left open.
Browser Compatibility: XHTML may not be supported by older browsers that were developed before it became a standard, while HTML has been around for a long time and is supported by almost all browsers.
Here’s an example of the difference between HTML and XHTML:
HTML:
<p>This is a paragraph</p>
XHTML:
<p>This is a paragraph</p>
In XHTML, every tag must be closed, so the above example is considered “well-formed”.
Another example:
HTML:
<img src=”example.jpg”>
XHTML:
<img src=”example.jpg” />
In XHTML, the tag must be closed with a forward slash to make it well-formed.
Overall, while both HTML and XHTML are used to create web pages, XHTML has a stricter syntax and requires tags to be closed, while HTML is more lenient and has been around for a long time.
What is the box model in CSS?
The box model in CSS is a concept used to describe how elements are laid out on a web page. It defines the dimensions and properties of each element as a rectangular box, consisting of content, padding, border, and margin.
Here’s a breakdown of each part of the box model:
Content: This is the actual content of the element, such as text or an image.
Padding: This is the space between the content and the border. It can be used to add space around the content, or to adjust the size of the element.
Border: This is a line that surrounds the element’s content and padding. It can be used to add visual separation between elements, or to add emphasis to an element.
Margin: This is the space between the border of the element and the surrounding elements. It can be used to create space between elements, or to center an element on the page.
Here’s an example of how the box model works in CSS:
.box {
width: 200px;
height: 100px;
padding: 10px;
border: 1px solid black;
margin: 20px;
}
What are some differences between CSS Grid and Flexbox?
CSS Grid and Flexbox are two powerful layout tools in CSS, each with its own unique features and use cases. Here are some differences between them:
Orientation: Flexbox is a one-dimensional layout model, meaning it deals with either rows or columns. CSS Grid, on the other hand, is a two-dimensional layout model, meaning it can handle both rows and columns simultaneously.
Layout types: Flexbox is best suited for creating flexible and dynamic layouts, such as those found in navigation bars or galleries. CSS Grid, on the other hand, is best suited for more complex and grid-based layouts, such as those found in websites with multiple sections or columns.
Alignment: Flexbox is primarily used for aligning and distributing items within a single row or column. CSS Grid, however, can align and distribute items across both rows and columns.
Nesting: Flexbox is designed to be nested, meaning it can be used inside other layout models like CSS Grid. CSS Grid, however, is not designed to be nested and is best used as the outermost layout model.
Browser support: While both Flexbox and CSS Grid are widely supported in modern browsers, there may be slight differences in browser support and syntax.
Here’s an example of using Flexbox for a simple layout:
.container {
display: flex;
flex-direction: row;
justify-content: space-between;
align-items: center;
}
.item {
flex: 1;
}
Explain the difference between server-side and client-side scripting.
Server-side scripting is used to access and modify data stored in a server, while client-side scripting is used to create interactive webpages on the client’s browser. Server-side scripting is typically done using languages like PHP, ASP, JSP or ColdFusion while client-side scripting is often done using JavaScript, HTML and CSS.
What is responsive web design and why is it important?
Responsive web design is a design approach that enables websites to be optimized for different devices, including desktop computers, tablets, and mobile phones. This is important because it allows users to access the website on their device of choice, regardless of whether they’re using a desktop computer, tablet, or mobile phone.
What is a RESTful API and how does it work?
A RESTful API is a type of web API that uses the principles of REST (Representational State Transfer) architecture. RESTful APIs allow for the creation, retrieval, update, and deletion of resources by clients over the web using HTTP requests.
The client makes requests to the server by sending HTTP methods such as GET, POST, PUT, and DELETE to URIs (Uniform Resource Identifiers) that represent resources. The server then responds with data in a structured format such as JSON or XML, which the client can use to render the resource or perform further actions.
What is the purpose of DNS and how does it work?
The purpose of DNS (Domain Name System) is to provide a globally addressable and hierarchical naming system for computers, services and other resources that are connected to the Internet. It is a key component of how the Internet functions, as it translates domain names into numerical addresses that computers can understand, allowing them to communicate with each other. It is essentially a phonebook for the Internet, mapping domain names to IP addresses so that computers can locate and communicate with each other.
What is a CDN and how does it improve website performance?
A content delivery network (CDN) is a system of distributed servers which deliver web content to users based on their geographical location. A CDN helps to improve website performance by caching the static elements of a website such as HTML, JavaScript, images and videos. This reduces latency, or the time it takes for a website to load, since these elements are delivered from the closest server and not from the origin server.
What is the difference between a session and a cookie?
A session and a cookie are both used to store information about a user. However, they work differently. A cookie is a small piece of data that is stored in the user’s browser and sent to the server with each request. This allows websites to remember information about a user, such as preferences or login information. A session, on the other hand, is a server-side storage mechanism that stores user data while they are browsing a website. Sessions are created when the user first visits a website and last until the user closes their browser, or the session expires. Unlike cookies, which are stored in the user’s browser, sessions are stored on the server. This means that session information is more secure and can be accessed from any device that has access to the server. Sessions are also more powerful than cookies, as they can store larger amounts of data and have greater flexibility.
What is the difference between GET and POST HTTP methods?
GET and POST are two different types of HTTP requests. The primary difference between them is that GET requests are used to retrieve daa from a server, while POST requests are used to send data to the server.
GET requests are generally used when retrieving data from a web page, such as when a user clicks on a link or submits a form. GET requests are sent to the server containing parameters in the URL, and results are sent back to the user in a response.
POST requests are used when submitting data to a server, such as when a user fills out a form. POST requests contain data in the body of the request, and results are also returned to the user in a response. POST requests are generally used for more substantial actions, such as creating a new record or updating an existing one.
Explain the concept of “same-origin policy” in web security.
The same-origin policy is a security feature implemented by web browsers that restricts a web page or script from accessing resources from a different origin. An origin is defined as the combination of protocol, domain name, and port number of a web page.
The same-origin policy helps prevent malicious scripts from stealing sensitive data by restricting access to resources from different origins. For example, a script loaded from website A is not allowed to access resources such as cookies or data from website B.
What is the difference between a website and a web application?
The main difference between a website and a web application is the functionality. A website is typically used to provide information or content to users, while a web application is used to enable users to perform specific tasks. Websites generally provide static content, while web applications typically provide dynamic content and interactivity. Websites are typically built using HTML, CSS, and JavaScript, while web applications are generally more complex and often involve the use of server-side scripting and databases.
Explain the concept of “caching” and how it can improve website performance.
Caching is the process of storing frequently accessed data in a temporary storage location, such as a browser cache or server cache. By caching data, websites can improve their performance and reduce load times. When a user visits a website that has cached data, the browser or server can retrieve the data from the cache instead of requesting it again from the original source. This reduces the amount of time and resources needed to load the page, resulting in faster load times and better user experience. Caching can also reduce network congestion and server load, leading to lower hosting costs and improved scalability. Overall, caching is an effective way to optimize website performance and enhance user satisfaction.
What is a CMS and how does it work?
A CMS, or Content Management System, is a software application that allows users to create, manage, and publish digital content. It typically consists of a back-end interface for content creation and management, and a front-end interface for content delivery to end-users. The back-end interface allows users to create and edit content using a variety of tools, such as text editors, image editors, and form builders. The CMS then stores the content in a database and delivers it to the front-end interface when requested by a user. The front-end interface is responsible for displaying the content to the user in a web browser. A CMS can be used for a variety of purposes, such as creating and managing websites, blogs, e-commerce stores, and more.
What is the difference between front-end and back-end development?
Front-end development focuses on the user experience and involves working with HTML, CSS, JavaScript, and related technologies to create websites and applications that can be interacted with by users. Back-end development focuses on the server-side components of a website or application and involves working with technologies such as databases, server-side scripts, and APIs to create the necessary functionality for a website or application. Both front-end and back-end development are essential components of web and app development, as they work together to create the entire user experience.
What is a framework and how does it differ from a library?
A framework is a set of tools and components that enable the development of applications. It provides developers with an organized structure for creating their applications. Unlike a library, a framework is designed to automate and manage many of the processes associated with developing applications. This includes configuration management, application deployment, application scaling, and data management.
A framework also provides developers with a set of conventions and guidelines for the development process, allowing them to easily integrate existing code and develop applications faster. Frameworks also provide developers with a common platform for developing applications across multiple platforms and environments, making it easier to create cross-platform applications.
In contrast, a library is a collection of code and functions that can be used to solve specific problems in an application. Libraries allow developers to easily access and use existing code to solve their problems, rather than having to write their own code from scratch. Libraries are often less structured than frameworks and provide developers with more flexibility in the development process.
What is MVC and how is it used in web development?
Model-View-Controller (MVC) is an architectural pattern used in software engineering. It divides a given application into three interconnected parts, namely the model, the view, and the controller. The model manages the data of the application; it contains all of the logic for handling data, such as creating, reading, updating and deleting (CRUD) data.
The view is responsible for displaying the application’s user interface and presenting the data from the model in a form that is usable by the user. Finally, the controller is responsible for processing requests from users and updating the model and view accordingly.
MVC is widely used in web application development, as it allows for a separation between the data and the presentation layers of the application.
What is the difference between a static website and a dynamic website?
A static website consists of web pages with fixed content that is hard-coded into the HTML and CSS files. These websites are simple and easy to create, but require manual editing of each page to make changes or updates.
A dynamic website, on the other hand, uses server-side scripting languages such as PHP or Python to generate content on the fly in response to user requests. This allows for more flexible and customizable content that can be updated automatically, such as user account information, search results, or product listings. Dynamic websites also often have back-end databases that store and manage the website’s content. Overall, dynamic websites offer greater functionality and interactivity than static websites, but can be more complex to create and maintain.
What is version control and what are some popular tools?
Version control is a system for managing changes to source code, documents, or any other files that may change over time. It allows developers or teams to track changes, collaborate on modifications, and revert to previous versions if necessary.
Some popular version control tools include Git, Subversion (SVN), and Mercurial. Git is a distributed version control system widely used by developers and teams for its speed, flexibility, and branching capabilities. SVN is a centralized version control system that provides a simpler workflow but with less advanced features than Git. Mercurial is another distributed version control system that shares many similarities with Git, but with a focus on simplicity and ease of use.