1. Which of the
following is a correct way to declare a variable in JavaScript?
A. variable x = 10;
B. var x = 10;
C. dim x = 10;
D. int x = 10;
Answer: B. var x = 10;
2. Which of the
following is not a valid JavaScript data type?
A. String
B. Boolean
C. Float
D. Object
Answer: C. Float
3. How do you create
a function in JavaScript?
A. function myFunction()
B. def myFunction()
C. function:myFunction()
D. create myFunction()
Answer: A. function myFunction()
4. Which builtin
method sorts the elements of an array?
A. changeOrder(order)
B. order()
C. sort()
D. arrange()
Answer: C. sort()
5. What is the
correct syntax for referring to an external script called
"script.js"?
A. <script href="script.js">
B. <script name="script.js">
C. <script src="script.js">
D. <script file="script.js">
Answer: C. <script
src="script.js">
6. How do you write
"Hello World" in an alert box?
A. msg("Hello World");
B. alertBox("Hello World");
C. msgBox("Hello World");
D. alert("Hello World");
Answer: D. alert("Hello World");
7. How do you call a
function named "myFunction"?
A. call myFunction()
B. call function myFunction()
C. myFunction()
D. Call.myFunction()
Answer: C. myFunction()
8. Which event occurs
when the user clicks on an HTML element?
A. onchange
B. onclick
C. onmouseclick
D. onmouseover
Answer: B. onclick
9. How do you declare
a JavaScript variable?
A. var carName;
B. variable carName;
C. v carName;
D. string carName;
Answer: A. var carName;
10. Which operator is
used to assign a value to a variable?
A. *
B. -
C. =
D. x
Answer: C. =
11. What is the correct JavaScript syntax to change the content of the HTML element below?
<p
id="demo">This is a demonstration.</p>
A. document.getElementById("demo").innerHTML
= "Hello World!";
B. document.getElementByName("p").innerHTML
= "Hello World!";
C. document.getElement("p").innerHTML
= "Hello World!";
D. demo.innerHTML = "Hello World!";
Answer: A. document.getElementById("demo").innerHTML
= "Hello World!";
12. How do you write
an IF statement in JavaScript?
A. if i == 5 then
B. if i = 5 then
C. if (i == 5)
D. if i = 5
Answer: C. if (i == 5)
13. How does a FOR
loop start?
A. for (i <= 5; i++)
B. for (i = 0; i <= 5; i++)
C. for (i = 0; i <= 5)
D. for i = 1 to 5
Answer: B. for (i = 0; i <= 5; i++)
14. How can you add a
comment in JavaScript?
A. 'This is a comment
B. <!This is a comment>
C. //This is a comment
D. **This
is a comment **h
Answer: C. //This is a comment
15. Which method
removes the last element from an array and returns that element?
A. pop()
B. last()
C. get()
D. None of the above
Answer: A. pop()
16. How can you
detect the client's browser name in JavaScript?
A. browser.name
B. client.navName
C. navigator.appName
D. browser.appName
Answer: C. navigator.appName
17. Which of the
following is not a reserved word in JavaScript?
A. interface
B. throws
C. program
D. short
Answer: C. program
18. How do you find
the number with the highest value of x and y in JavaScript?
A. Math.max(x, y)
B. Math.ceil(x, y)
C. Math.floor(x, y)
D. ceil(x, y)
Answer: A. Math.max(x, y)
19. Which of the
following is a valid way to create an array in JavaScript?
A. var arr = new Array();
B. var arr = [];
C. var arr = new Array(5);
D. All of the above
Answer: D. All of the above
20. How do you round
the number 7.25 to the nearest integer?
A. rnd(7.25)
B. Math.rnd(7.25)
C. Math.round(7.25)
D. round(7.25)
Answer: C. Math.round(7.25)
21. Which of the
following is not a JavaScript framework or library?
A. React
B. Angular
C. Vue
D. Cassandra
Answer: D. Cassandra
22. How do you add a
property to an object in JavaScript?
A. object.property = value;
B. object>property = value;
C. object::property = value;
D. object|property = value;
Answer: A. object.property = value;
23. Which operator is
used to compare both value and type in JavaScript?
A. ==
B. ===
C. !=
D. !==
Answer: B. ===
24. What is the
correct way to write a JavaScript array?
A. var colors = "red",
"green", "blue";
B. var colors = 1 = ("red"), 2 =
("green"), 3 = ("blue");
C. var colors = ["red",
"green", "blue"];
D. var colors = (1:"red",
2:"green", 3:"blue");
Answer: C. var colors = ["red",
"green", "blue"];
25. How do you write
a switch statement in JavaScript?
A. switch x { case 1: break; case 2: break; }
B. switch(x) { case 1: break; case 2: break; }
C. switch(x) { case: 1; break; case: 2; break;
}
D. switch { x case 1: break; case 2: break; }
Answer: B. switch(x) { case 1: break; case 2:
break; }
26. How do you create
a new object in JavaScript?
A. var obj = {};
B. var obj = new Object();
C. var obj = Object.create(null);
D. All of the above
Answer: D. All of the above
27. Which method is
used to convert a JSON text into a JavaScript object?
A. JSON.parse()
B. JSON.stringify()
C. JSON.convert()
D. JSON.toObject()
Answer: A. JSON.parse()
28. How do you check
if a variable is an array in JavaScript?
A. Array.isArray(variable)
B. variable.isArray()
C. typeof variable === 'array'
D. variable instanceof Array
Answer: A. Array.isArray(variable)
29. What is the
result of the following expression: "5" + 2?
A. 52
B. 7
C. NaN
D. undefined
Answer: A. 52
30. What will be the output of the following code?
console.log(typeof NaN);
A. number
B. string
C. object
D. undefined
Answer: A. number
31. Which method is
used to add elements to the end of an array?
A. push()
B. append()
C. add()
D. insert()
Answer: A. push()
32. What is the output of the following code?
console.log(0.1 +
0.2 === 0.3);
A. true
B. false
C. undefined
D. NaN
Answer: B. false
33. Which method is
used to remove whitespace from both ends of a string?
A. trim()
B. strip()
C. cut()
D. clear()
Answer: A. trim()
34. What is the
purpose of the bind() method in JavaScript?
A. To bind a function to an object.
B. To call a function with a specific this
value.
C. To create a new function with the same body
as an existing function.
D. To change the context of a function.
Answer: A. To bind a function to an object.
35. How do you get
the length of an array in JavaScript?
A. array.length
B. array.size
C. array.count
D. array.len
Answer: A. array.length
36. What will the following code output?
console.log("Hello" === "hello");
A. true
B. false
C. undefined
D. NaN
Answer: B. false
37. How do you
comment out a block of code in JavaScript?
A. / Comment /
B. <! Comment >
C. // Comment //
D. ( Comment )
Answer: A. / Comment /
38. What is the output of the following code?
console.log(typeof
null);
A. object
B. null
C. undefined
D. string
Answer: A. object
39. How do you create
a date object in JavaScript?
A. new Date()
B. Date()
C. create Date()
D. create new Date()
Answer: A. new Date()
40. What does the isNaN
function do?
A. Checks if a value is null.
B. Checks if a value is not a number.
C. Checks if a value is undefined.
D. Checks if a value is a number.
Answer: B. Checks if a value is not a number.
41. Which of the
following is not a JavaScript loop structure?
A. for
B. foreach
C. while
D. dowhile
Answer: B. foreach
42. What does NaN
stand for?
A. Not a Number
B. Not a Null
C. Null and Not defined
D. None of the Above
Answer: A. Not a Number
43. Which of the
following is used to check if a property is in an object?
A. in operator
B. has operator
C. exists operator
D. None of the above
Answer: A. in operator
44. What will the following code output?
console.log(typeof
undefined == typeof NULL);
A. true
B. false
C. undefined
D. null
Answer: A. true
45. Which of the
following is not a valid JavaScript variable name?
A. _myVar
B. $myVar
C. myvar
D. myVar
Answer: C. myvar
46. What is the result of the following code?
console.log("5" 3);
A. 2
B. 8
C. NaN
D. 53
Answer: A. 2
47. How do you create
an object in JavaScript?
A. var obj = {};
B. var obj = new Object();
C. var obj = Object.create(null);
D. All of the above
Answer: D. All of the above
48. What is the
output of the following code?
console.log(typeof
function() {});
A. object
B. function
C. undefined
D. null
Answer: B. function
49. Which method is
used to remove the first element from an array and return that element?
A. shift()
B. unshift()
C. pop()
D. splice()
Answer: A. shift()
50. How do you add an
element to the beginning of an array?
A. push()
B. unshift()
C. shift()
D. append()
Answer: B. unshift()
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