🚀 Top 200 Web Development Interview Questions

🧠 1. HTML Interview Questions (1–20)
1. What is HTML?
2. Difference between HTML4 and HTML5
3. What are semantic tags in HTML5?
4. Difference between <div> and <span>
5. What is the purpose of DOCTYPE?
6. What are meta tags?
7. Difference between ID and Class
8. What are inline and block elements?
9. Explain forms in HTML
10. Difference between GET and POST
11. What is localStorage and sessionStorage?
12. What are data attributes?
13. What is iframe?
14. Difference between cookies and localStorage
15. What are void elements?
16. What is the purpose of alt attribute?
17. Explain audio and video tags
18. What is accessibility in HTML?
19. What are ARIA attributes?
20. What is the difference between strong and b tags?

🎨 2. CSS Interview Questions (21–45)
21. What is CSS?
22. Difference between inline, internal, and external CSS
23. What is specificity in CSS?
24. Explain CSS Box Model
25. Difference between margin and padding
26. What is Flexbox?
27. What is CSS Grid?
28. Difference between relative, absolute, fixed, and sticky positioning
29. What is z-index?
30. Difference between em, rem, %, px, vh, and vw
31. What are pseudo-classes?
32. What are pseudo-elements?
33. Difference between visibility:hidden and display:none
34. What is media query?
35. Explain responsive design
36. What is mobile-first design?
37. What are CSS transitions?
38. Difference between transition and animation
39. What is transform property?
40. What is overflow property?
41. Explain CSS inheritance
42. What is !important?
43. What are CSS preprocessors?
44. Difference between SCSS and SASS
45. What is Bootstrap?

⚡ 3. JavaScript Basics (46–80)
46. What is JavaScript?
47. Difference between var, let, and const
48. What are data types in JavaScript?
49. Difference between null and undefined
50. What is hoisting?
51. Explain scope in JavaScript
52. What is closure?
53. What is callback function?
54. What is arrow function?
55. Difference between == and ===
56. What is event bubbling?
57. What is event capturing?
58. What is event delegation?
59. What is DOM?
60. Difference between synchronous and asynchronous programming
61. What is promise in JavaScript?
62. What are async and await?
63. What is setTimeout?
64. Difference between map(), filter(), and reduce()
65. What is destructuring?
66. What is spread operator?
67. What is rest operator?
68. What is template literal?
69. What is optional chaining?
70. Explain this keyword
71. Difference between function declaration and expression
72. What is prototype?
73. What is prototypal inheritance?
74. What is JSON?
75. Difference between localStorage and sessionStorage
76. What is NaN?
77. What are truthy and falsy values?
78. What is debounce?
79. What is throttle?
80. What is currying?

⚛️ 4. ReactJS Interview Questions (81–110)
81. What is React?
82. What are components in React?
83. Difference between functional and class components
84. What is JSX?
85. What are props?
86. What is state?
87. Difference between state and props
88. What is useState hook?
89. What is useEffect hook?
90. What is virtual DOM?
91. What is reconciliation?
92. What are keys in React?
93. What is prop drilling?
94. What is Context API?
95. What is Redux?
96. Difference between Redux and Context API
97. What are React hooks?
98. What is useRef?
99. What is useMemo?
100. What is useCallback?
101. What is lazy loading in React?
102. What is React Router?
103. What are controlled components?
104. What are uncontrolled components?
105. What is lifting state up?
106. What is Higher Order Component (HOC)?
107. What are custom hooks?
108. What is Strict Mode?
109. What is server-side rendering?
110. Difference between CSR and SSR