Front-end Interview Question and Answer , Web developer interview question and Answer:
Q: How to explain yourself during an interview?
Short Syntax and Answers
A: Describe your background, skills, experiences, and why you are suitable for the job. Highlight key achievements and
how they relate to the position.
Q: What is HTML?
A: HTML (HyperText Markup Language) is the standard language for creating web pages and web applications.
Q: What is DOCTYPE?
A: DOCTYPE is an instruction to the web browser about the version of HTML the page is written in.
Q: HTML 4 and HTML5 differences?
A: HTML5 includes new elements (e.g., <article>, <section>), audio and video support, and improved form controls
compared to HTML4.
Q: div and span difference?
A: <div> is a block-level element, while <span> is an inline element.
Q: Semantic tags in HTML5?
A: Examples include <article>, <section>, <nav>, <header>, and <footer>.
Q: Form elements tags in HTML5?
A: New form elements include <datalist>, <output>, <progress>, <meter>, <keygen>, and <input type='date>.
Q: meta tag in HTML5?
A: Provides metadata about the HTML document, such as charset, viewport settings, and keywords.
Q: title tag in HTML?
A: Defines the title of the document, shown in the browser's title bar or tab.
Q: Head and body content?
A: The <head> contains metadata, links to stylesheets, and scripts; the <body> contains the actual content of the
webpage.
Q: Favicon?
A: A small icon displayed in the browser tab, usually linked in the <head> with <link rel='icon'>.
Q: Structured HTML?
A: Organized and well-nested HTML that improves readability and maintainability.
Q: alt attribute in image?
A: Provides alternative text for an image if it cannot be displayed.
Q: h1 to h6 font sizes?
A: Font sizes typically decrease from <h1> (largest) to <h6> (smallest), with default sizes being browser-dependent.
Q: What is CSS?
A: CSS (Cascading Style Sheets) is a style sheet language used to describe the presentation of HTML documents.
Q: Difference between HTML & CSS?
A: HTML structures content, while CSS styles it.
Q: CSS properties: absolute, relative, fixed?
A: Absolute: positioned relative to the nearest positioned ancestor. Relative: positioned relative to its normal position.
Fixed: positioned relative to the viewport.
Q: display: inline-block, display: block?
A: Inline-block: elements are inline but respect width and height. Block: elements take up the full width available.
Q: Overlay in CSS?
A: A layer that sits on top of another element, often created using position: absolute or position: fixed with appropriate
z-index.
Q: !important in CSS?
A: Overrides other styles regardless of specificity.
Q: Internal CSS and external CSS?
A: Internal CSS is within a <style> tag in the HTML file; external CSS is in a separate .css file linked with <link>.
Q: Bootstrap and its version?
A: Bootstrap is a front-end framework for developing responsive websites. The latest version as of now is Bootstrap 5.
Q: Grid in Bootstrap?
A: A system for creating layouts using rows and columns, responsive across different screen sizes.
Q: What is JS?
A: JavaScript (JS) is a programming language used to create interactive effects within web browsers.
Q: What is DOM?
A: The Document Object Model (DOM) is a programming interface for web documents, representing the structure as a
tree of objects.
Q: Virtual DOM?
A: A lightweight copy of the DOM used to optimize updates and improve performance in frameworks like React.
Q: Browser Object Model?
A: Represents browser window components and allows interaction with the browser (e.g., window, navigator).
Q: HTML element to JS access?
A: Use methods like getElementById, querySelector, or getElementsByClassName.
Q: Event in JS?
A: An action or occurrence detected by JavaScript, such as clicks or key presses, that can trigger a response.
Q: Array in JS?
A: A collection of elements stored in a single variable, accessible by index.
Q: Object in JS?
A: A collection of key-value pairs, where keys are strings and values can be any data type.
Q: Map in JS?
A: A collection of key-value pairs, where keys can be any data type and values are mapped to these keys.
Q: Loop in JS?
A: Structures for repeated execution of code, such as for, while, and do...while loops.
Q: for, for...in, forEach in JS?
A: for loops iterate over indices, for...in loops over object properties, forEach iterates over array elements.
Q: Promise in JS?
A: An object representing the eventual completion (or failure) of an asynchronous operation and its resulting value.
Q: Blocking and unblocking in JS?
A: Blocking operations stop further execution until complete; non-blocking (asynchronous) operations allow other tasks
to run concurrently.
Q: Async & Await in JS?
A: Keywords for handling asynchronous operations more easily, allowing asynchronous code to be written like
synchronous code.
Q: What is TypeScript?
A: A superset of JavaScript that adds static types and other features to enhance development.
Q: let, var & const in JS?
A: let and const are block-scoped, while var is function-scoped. const defines constants.
Q: Callback function in JS?
A: A function passed as an argument to another function, to be executed after the first function completes.
Q: Palindrome string in JS?
A: A string that reads the same forwards and backwards. Check using string reversal and comparison.
Q: String reverse in JS?
A: Reverse a string by splitting it into an array, reversing the array, and joining it back into a string.
Q: Array max in JS?
A: Find the maximum value in an array using Math.max with the spread operator.
Q: Combine two arrays in JS?
A: Combine using the concat method or the spread operator.
Q: Split paragraph into sentences in JS?
A: Use the split method with a period (or other sentence-ending punctuation) as the delimiter.
Q: Maximum word in paragraph in JS?
A: Split the paragraph into words, then use a frequency count to find the word with the maximum occurrences
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