Top 25+ Most Asked Front end Developer Interview Questions and Answers
1) What are the main technical and additional skills required to become a front-end developer?
A candidate must obtain the following technical and additional skills to become a front-end developer:
Must Required Skills:
Apart from the above mentioned technical skills, a good front-end developer should have the following skills and knowledge:
2) What are some most used Git Commands and functions?
Following is a list of some most used Git Commands and functions:
3) How can you make your web design user-friendly, and what steps would you use to make it?
A front-end developer must follow the steps given below to make their web design user-friendly:
4) What do you understand by Version Control System?
A Version Control System (VCS) is a program that is used to record any changes to a file or set of data so that we can restore it to a previous version if needed. It ensures that everyone on the team is working on the most up-to-date file version.
5) What is Coffee Script? Describe in brief.
6) What do you understand by a callback function?
A callback function is a function that is passed as an argument to another function and ensures that a function is not going to run before a task is completed. This function runs right after the task has been completed.
7) What do you understand by clear?
A clear is used when we don't need an element to wrap around another element, like float.
9) What are the key differences between XHTML and HTML?
HTML and XHTML, both are markup languages. Let's see the key differences between them:
11) What do you understand by the CSS box model?
The CSS box model is a way to handle CSS layout. This term is used when we talk about the design and layout of th elements. Each element is composed of its content, padding, border, and margin.
In other words, we can say that the CSS box model is essentially a box that wraps around every HTML element.
12) What is the difference between Git Pull and Git Fetch commands?
Git pull and Git fetch are the Git commands used to make changes and retrieve data. Let's see the key differences between them:
13) What do you know about CSS Selectors?
CSS selectors are used to selecting or finding the HTML elements you want to style and make changes in their style. CSS selectors can be divided into the following five categories:
14) What is the key difference between Class and Prototype-based inheritance?
16) What is the difference between Visibility:Hidden;and Display:None;?
The Visibility:Hidden; and Display:None; both are used in front-end development when we don't want to display things on the screen.
17) What is the importance of HTML DOCTYPE?
In HTML, the DOCTYPE declaration points to a Document Type Definition (DTD). It is used to instruct the web browser about what version of the markup language the page is written. The DOCTYPE declaration is written as the first thing in the HTML document, before the <html> tag. It is a set of markup language rules that makes the browser easily and correctly interpret the content written within.
18) What is the key difference between a host object and a native object?
19) What is a marquee in HTML?
In HTML, a marquee is a scrolling piece of text displayed on the webpage. According to the marquee settings, it is either scrolled horizontally across or vertically up or down your web page. The marquee effect is created by using HTML <marquee> tag, which automatically scrolls the text or images up, down, left, or right.
20) What is the key difference between cookies, session storage, and local storage?
Difference between cookies, session storage, and local storage
21) What do you understand by Semantic HTML? How does it work?
Semantic HTML is a type of coding that uses HTML markup to reinforce the semantics or meaning of the information in web pages and web applications rather than merely to define its presentation or look. Semantic HTML is processed by traditional web browsers and many other user agents. It is used to emphasize the content's semantics or meaning.
The tags are different in semantic HTML as compared to normal HTML. For example, the <b></b> tag is not used for bold statements in semantic HTML, and the <i></i> element is for italic. Instead, we use the <strong></strong> tags and <em></em> tags respectively.
22) What do you understand by Web Accessibility?
Web Accessibility is a way to design, develop, and code websites and web tools that people with disabilities can also use. It makes using the technology easy for certain people who have difficulties hearing or seeing. It ensures that the web is also usable by people with a wide range of disabilities.
23) What is the difference between Git Merge and Git Rebase?
Git merge, and Git rebase are both used to integrate changes from one branch into another. Git rebase moves a feature branch into a master while the Git merge adds a new commit, preserving the history.
According to the official Git manual, the Git Rebase "reapplies commits on top of another base branch". On the other hand, Git merge "joins two or more development histories together". In other words, we can see that the Git merge preserves history as it happened, while the Git rebase rewrites it.
For example, if you are working on a new feature in a dedicated branch, and another team member pushes new commits to the master branch, the Git merge will incorporate new commits into your feature branch. Every time you need to include modifications, you would require an extra merging commit. On the other hand, in Git rebase, you can rebase the feature branch into master instead of merging it. This includes all the new commits in the master branch and rewrites the project history by creating brand new commits for each one in the original branch.
25) What do you understand by lazy loading? What are the advantages and disadvantages of lazy loading?
Lazy loading is a design pattern and optimization technique used in computer programming to delay the initialization of an object until a required period. It is also known as on-demand loading. This optimization technique is used for online content like a website or a web app. It is used to enhance the performance of the web page. In this technique, instead of loading the entire web page and rendering it to the user in one go as in bulk loading, only the required section is loaded, and it delays the remaining part of the web page until the user requires it.
Advantages of Lazy loading
Disadvantages of Lazy loading
26) What is the syntax of using a function as a class?
Following is the syntax of using a function as a class:
27) What is the difference between a tag and an attribute in HTML?
Tags and attributes are two concepts used in HTML. They work together but perform different functions. The main difference between an HTML tag and an HTML attribute is that an HTML tag is a way of representing an HTML element in the program. On the other hand, an HTML attribute describes the characteristics of an HTML element. For example, <a>, <href>, <button>, and <div> etc. are HTML tags and src, class, and id etc. are the example of HTML attributes.
See this example:
In the above example, the image source (src) and the alt text (alt) are attributes of the <img> tag.
Difference between HTML tags and HTML attributes
28) What is CSS float?
CSS float is a property that is used to specify whether an element should float to the left, right, or not at all. It is used when we have to push our web page element left or right and make all other elements cover around it.
29) What is the difference between inline and block elements in HTML?
The HTML inline and block elements are important areas of front-end development. Let us see the differences between the inline and block elements in HTML:
Block Elements: Block elements are types of blocks that contain many elements in a line itself. They consider top and bottom margins and don't contain any other elements next to them. They consume the full width available and always start in a new line.
Examples of Block elements:
HTML 5 Semantic block elements:
Inline Elements: Inline elements take up only enough width that is sufficient to them and allow other elements next to it inline. They do not have top and bottom margins as block elements have only the left and right and consider the padding.
Examples of Inline elements: