BFE
.dev
buy us
a coffee
EN
Practice
Explore
EN
JavaScript Quizzes
Test your knowledge of JavaScript the language itself.
Sort
Difficulty
Solved status
Sort: easiest
79. Equal III
JavaScript
easy
69% accepted
99. closure
JavaScript
easy
64% accepted
105. typeof
JavaScript
easy
64% accepted
2. Promise executor
JavaScript
Promise
easy
63% accepted
69. undefined
JavaScript
easy
62% accepted
104. Inheritance
JavaScript
easy
59% accepted
46. Implicit Coercion IV
JavaScript
easy
59% accepted
111. falsy
JavaScript
easy
59% accepted
40. RegExp.prototype.test
JavaScript
easy
59% accepted
89. let
JavaScript
easy
58% accepted
34. precedence
JavaScript
easy
58% accepted
44. Function call
JavaScript
easy
58% accepted
59. override setter
JavaScript
easy
57% accepted
37. push unshift
JavaScript
easy
57% accepted
71. two-way generator
JavaScript
easy
57% accepted
63. in
JavaScript
easy
57% accepted
107. `this` VI
JavaScript
easy
57% accepted
66. comma
JavaScript
easy
57% accepted
101. Equal IV
JavaScript
easy
56% accepted
39. var
JavaScript
easy
56% accepted
13. Operator precedence
JavaScript
easy
55% accepted
74. Typed Array length
JavaScript
easy
55% accepted
45. Hoisting VI
JavaScript
easy
55% accepted
53. Prototype 2
JavaScript
easy
55% accepted
124. comma 2
JavaScript
easy
52% accepted
75. meaningless calculation
JavaScript
easy
52% accepted
57. non-writable
JavaScript
easy
52% accepted
18. Promise executor II
JavaScript
easy
50% accepted
91. largest Array index
JavaScript
easy
50% accepted
106. Promise.all() II
JavaScript
easy
50% accepted
28. Hoisting II
JavaScript
easy
49% accepted
115. parseInt II
JavaScript
easy
49% accepted
31. Math
JavaScript
easy
48% accepted
112. Symbol
JavaScript
easy
48% accepted
86. setTimeout III
JavaScript
easy
48% accepted
48. Prototype
JavaScript
easy
48% accepted
24. Equality & Sameness
JavaScript
easy
47% accepted
58. inherit getter setter
JavaScript
easy
47% accepted
33. `this` II
JavaScript
easy
47% accepted
100. `var` vs `let`
JavaScript
easy
47% accepted
103. Promise Order III
JavaScript
easy
45% accepted
96. comparison
JavaScript
easy
45% accepted
102. Arrow Function II
JavaScript
easy
45% accepted
94. emoji
JavaScript
easy
45% accepted
22. min max
JavaScript
easy
44% accepted
65. Function name
JavaScript
easy
44% accepted
54. setTimeout(0ms)
JavaScript
easy
44% accepted
7. Increment Operator
JavaScript
easy
43% accepted
49. `this` IV
JavaScript
easy
43% accepted
109. isNaN()
JavaScript
easy
43% accepted
26. true or false
JavaScript
easy
43% accepted
5. scope
JavaScript
easy
42% accepted
122. Iterable
JavaScript
easy
42% accepted
23. Promise.all()
JavaScript
easy
42% accepted
108. property key
JavaScript
easy
41% accepted
3. Promise then callbacks
JavaScript
Promise
easy
41% accepted
30. Equal II
JavaScript
easy
40% accepted
41. `this` III
JavaScript
easy
40% accepted
61. onClick
JavaScript
easy
40% accepted
110. yield
JavaScript
easy
39% accepted
35. Implicit Coercion III
JavaScript
easy
39% accepted
98. Promise executor IV
Promise
easy
39% accepted
60. postMessage
JavaScript
easy
39% accepted
52. requestAnimationFrame
JavaScript
easy
39% accepted
47. Promise Order II
JavaScript
easy
38% accepted
62. MessageChannel
JavaScript
easy
38% accepted
87. instanceOf 2
JavaScript
easy
38% accepted
93. string
JavaScript
easy
38% accepted
10. Equal
JavaScript
easy
38% accepted
27. Hoisting I
JavaScript
easy
38% accepted
29. Hoisting III
JavaScript
easy
37% accepted
92. NaN
JavaScript
easy
37% accepted
15. instanceOf
JavaScript
easy
37% accepted
72. Array length
JavaScript
easy
37% accepted
81. setTimeout II
JavaScript
easy
36% accepted
80. Proxy I
JavaScript
easy
36% accepted
38. Hoisting IV
JavaScript
easy
36% accepted
123. return in Generator 2
JavaScript
easy
36% accepted
95. number format
JavaScript
easy
36% accepted
64. reference type
JavaScript
easy
36% accepted
77. parseInt 2
JavaScript
easy
35% accepted
130. async
JavaScript
easy
35% accepted
83. Plus Plus
JavaScript
easy
34% accepted
56. to primitive
JavaScript
easy
34% accepted
82. Proxy II
JavaScript
easy
34% accepted
16. parseInt
JavaScript
easy
34% accepted
118. structuredClone()
JavaScript
easy
34% accepted
97. `this` V
JavaScript
easy
34% accepted
120. try..catch..finally
JavaScript
easy
33% accepted
50. async await
JavaScript
easy
33% accepted
116. strict
JavaScript
easy
33% accepted
1. Promise order
JavaScript
Promise
easy
33% accepted
117. `this` VII
JavaScript
easy
33% accepted
36. Promise.prototype.finally()
JavaScript
easy
33% accepted
70. function
JavaScript
easy
33% accepted
19. `this`
JavaScript
easy
32% accepted
114. constructor
JavaScript
easy
32% accepted
129. Function II
JavaScript
few challengers
32% accepted
25. zero
JavaScript
easy
32% accepted
4. Promise then callbacks II
JavaScript
Promise
easy
32% accepted
14. Addition vs Unary Plus
JavaScript
easy
32% accepted
8. Implicit Coercion I
JavaScript
easy
32% accepted
32. Hoisting IIII
JavaScript
easy
31% accepted
11. Implicit Coercion II
JavaScript
easy
31% accepted
88. try...catch
JavaScript
easy
31% accepted
67. if
JavaScript
easy
30% accepted
17. reduce
JavaScript
medium
30% accepted
9. null and undefined
JavaScript
medium
30% accepted
113. push
JavaScript
medium
29% accepted
85. String.raw()
JavaScript
medium
29% accepted
125. try...catch...finally 2
JavaScript
medium
29% accepted
119. return in Generator
JavaScript
medium
27% accepted
128. setTimeout IV
JavaScript
medium
27% accepted
6. Arrow Function
JavaScript
medium
27% accepted
84. Array.prototype.sort()
JavaScript
medium
26% accepted
121. Generator return()
JavaScript
medium
26% accepted
126. Object.keys()
JavaScript
medium
25% accepted
43. JSON.stringify()
JavaScript
medium
25% accepted
42. Hoisting V
JavaScript
medium
25% accepted
90. array keys
JavaScript
medium
24% accepted
68. if II
JavaScript
medium
24% accepted
20. name for Function expression
JavaScript
medium
24% accepted
21. Array I
JavaScript
medium
23% accepted
55. sparse array
JavaScript
medium
21% accepted
51. method
JavaScript
medium
20% accepted
78. RegExp
JavaScript
RegExp
medium
20% accepted
127. JSON.stringify() II
JavaScript
medium
20% accepted
73. window name
JavaScript
medium
20% accepted
12. arguments
JavaScript
medium
18% accepted
131. return await
JavaScript
14% accepted
76. const
JavaScript
hard?
10% accepted