1. Which type of language is JavaScript?
a) Object-Oriented
b) Object-Based
c) Assembly-language
d) High-level
✔️ Answer: b) Object-Based
2. Inside which HTML element do we put the JavaScript?
a) <js>
b) <scripting>
c) <script>
d) <javascript>
✔️ Answer: c) <script>
3. What is the correct syntax for referring to an external script?
a) <script src="app.js">
b) <script href="app.js">
c) <script ref="app.js">
d) <script link="app.js">
✔️ Answer: a) <script src="app.js">
4. How do you write “Hello World” in an alert box?
a) alertBox("Hello World");
b) msgBox("Hello World");
c) msg("Hello World");
d) alert("Hello World");
✔️ Answer: d) alert("Hello World");
5. JavaScript is a ________ Side Scripting Language.
a) Server
b) Browser
c) Client
d) Both a and c
✔️ Answer: d) Both a and c
6. Which of the following is the correct JavaScript syntax to change the content of the HTML element below?
<p id="demo">This is a demo.</p>
a) document.getElementByName("p").innerHTML = "Hello";
b) document.getElement("p").innerHTML = "Hello";
c) document.getElementById("demo").innerHTML = "Hello";
d) document.getId("demo").innerHTML = "Hello";
✔️ Answer: c) document.getElementById("demo").innerHTML = "Hello";
7. Which event occurs when the user clicks on an HTML element?
a) onmouseover
b) onchange
c) onclick
d) onmouseclick
✔️ Answer: c) onclick
8. How do you declare a JavaScript variable?
a) var name;
b) v name;
c) dim name;
d) string name;
✔️ Answer: a) var name;
9. What will typeof null return?
a) “null”
b) “object”
c) “undefined”
d) “number”
✔️ Answer: b) “object”
10. What does NaN stand for?
a) Not a Name
b) Not a Number
c) Name as Number
d) Null as Number
✔️ Answer: b) Not a Number
11. What is the correct way to write a JavaScript array?
a) var colors = (1:"red", 2:"green", 3:"blue")
b) var colors = "red", "green", "blue"
c) var colors = ["red", "green", "blue"]
d) var colors = 1 = ("red"), 2 = ("green"), 3 = ("blue")
✔️ Answer: c) var colors = ["red", "green", "blue"]
12. Which symbol is used for comments in JavaScript?
a) //
b) <!-- -->
c) **
d) #
✔️ Answer: a) //
13. How do you create a function in JavaScript?
a) function = myFunction()
b) function myFunction()
c) function:myFunction()
d) create myFunction()
✔️ Answer: b) function myFunction()
14. What is the output of console.log(typeof [])?
a) array
b) object
c) list
d) string
✔️ Answer: b) object
15. Which operator is used to assign a value to a variable?
a) =
b) ==
c) :=
d) ===
✔️ Answer: a) =
16. What is the output of console.log(2 + '2')?
a) 4
b) “22”
c) NaN
d) Error
✔️ Answer: b) “22”
17. Which keyword is used to check whether a value is not a number?
a) isNaN()
b) isNan()
c) NaN()
d) nonNumber()
✔️ Answer: a) isNaN()
18. What does the push() method do?
a) Removes last element
b) Adds an element at the end
c) Adds an element at the beginning
d) Sorts the array
✔️ Answer: b) Adds an element at the end
19. Which method converts JSON to a JavaScript object?
a) JSON.convert()
b) JSON.parse()
c) JSON.stringify()
d) JSON.toJS()
✔️ Answer: b) JSON.parse()
20. Which method returns the character at the specified index?
a) charAt()
b) getChar()
c) characterAt()
d) indexChar()
✔️ Answer: a) charAt()
21. Which function of Array joins all elements into a string?
a) join()
b) merge()
c) convert()
d) toString()
✔️ Answer: a) join()
22. What will typeof undefined return?
a) “null”
b) “undefined”
c) “object”
d) “error”
✔️ Answer: b) “undefined”
23. What is the output of 10 + true?
a) 10
b) 11
c) NaN
d) Error
✔️ Answer: b) 11
24. What is === in JavaScript?
a) Assignment
b) Compare values only
c) Strict equality (value + type)
d) Type check only
✔️ Answer: c) Strict equality (value + type)
25. How do you stop a loop in JavaScript?
a) break
b) stop
c) halt
d) exit
✔️ Answer: a) break
26. Which of these is not a JavaScript loop structure?
a) for
b) while
c) foreach
d) loop
✔️ Answer: d) loop
27. Which method removes the last element of an array?
a) pop()
b) push()
c) shift()
d) remove()
✔️ Answer: a) pop()
28. Which statement is used to skip an iteration in a loop?
a) break
b) continue
c) skip
d) pass
✔️ Answer: b) continue
29. What is the default value of uninitialized variable in JavaScript?
a) null
b) undefined
c) 0
d) false
✔️ Answer: b) undefined
30. How can you convert a string to a number in JavaScript?
a) Number()
b) parseInt()
c) parseFloat()
d) All of the above
✔️ Answer: d) All of the above
31. Which object in JavaScript lets you work with dates and times?
a) Date
b) Time
c) Calendar
d) Clock
✔️ Answer: a) Date
32. Which keyword is used to define a constant in JS?
a) constant
b) let
c) const
d) define
✔️ Answer: c) const
33. What is Math.floor(4.7)?
a) 5
b) 4.7
c) 4
d) 0
✔️ Answer: c) 4
34. Which method can be used to find the length of a string?
a) count()
b) length()
c) len
d) .length
✔️ Answer: d) .length
35. Which operator is used to compare both value and type?
a) ==
b) =
c) ===
d) :=
✔️ Answer: c) ===
36. JavaScript is ______ typed.
a) Statically
b) Dynamically
c) Strongly
d) Loosely
✔️ Answer: b) Dynamically
37. What does setTimeout() do?
a) Repeats code forever
b) Executes code once after delay
c) Loops code
d) Stops execution
✔️ Answer: b) Executes code once after delay
38. Which method executes a function once after a specified time?
a) setInterval()
b) setDelay()
c) setTimeout()
d) setPause()
✔️ Answer: c) setTimeout()
39. What is closure in JavaScript?
a) Object inside array
b) Function with private variables
c) Function that stops execution
d) None
✔️ Answer: b) Function with private variables
40. How to write an arrow function?
a) (x) => x * 2
b) ->(x) x * 2
c) (x) => { return x * 2; }
d) Both a and c
✔️ Answer: d) Both a and c
41. isNaN("123") returns:
a) true
b) false
c) NaN
d) Error
✔️ Answer: b) false
42. Which keyword creates a block-scoped variable?
a) var
b) block
c) let
d) scope
✔️ Answer: c) let
43. Which built-in method reverses the order of the elements in an array?
a) changeOrder(order)
b) reverse()
c) order()
d) sort(order)
✔️ Answer: b) reverse()
44. How do you check if x is an array?
a) typeof x === 'array'
b) x.isArray()
c) Array.isArray(x)
d) x instanceof array
✔️ Answer: c) Array.isArray(x)
45. What is a callback function?
a) Function passed into another function
b) Loop function
c) Static function
d) Recursive function
✔️ Answer: a) Function passed into another function
46. What is the scope of a variable declared with let?
a) Global
b) Local
c) Block
d) Function
✔️ Answer: c) Block
47. What is the output of true + false?
a) 1
b) truefalse
c) NaN
d) Error
✔️ Answer: a) 1
48. JavaScript can run outside the browser using?
a) Chrome only
b) Node.js
c) React.js
d) Angular
✔️ Answer: b) Node.js
49. What will console.log(typeof NaN) output?
a) number
b) NaN
c) undefined
d) object
✔️ Answer: a) number
50. What does the shift() method do in an array?
a) Adds to the end
b) Removes the last item
c) Removes the first item
d) Adds to the front
✔️ Answer: c) Removes the first item
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