JavaScript Interview Questions and Answers
This is an interactive multiple-choice JavaScript quiz that allows you to test your knowledge of JavaScript by answering the following questions.
1) What is the output of following JavaScript code?
a) 44
b) 8
c) 4
d) Error output
2) What is the output of following JavaScript code?
var cst = "Scripts Software Technologies";
var result = cst.split(" ");
document.write(result);
a) Scripts
b) S,c,i,p,t,s,S,o,f,t,w,a,r,e,T,e,c,h,n,o,l,o,g,i,e,s
c) Scripts,Software,Technologies
d) Scripts Software Technologies
3) Is it possible to nest functions in JavaScript?
a) True
b) False
4) What is the output of following JavaScript code?
a) get code name of the browser of a visitor
b) set code name of the browser of a visitor
c) None of the above
5) Which of the following is true?
a) If onKeyDown returns false, the key-press event is cancelled.
b) If onKeyPress returns false, the key-down event is cancelled.
c) If onKeyDown returns false, the key-up event is cancelled.
d) If onKeyPress returns false, the key-up event is canceled.
6) Scripting language is
a) High Level Programming language
b) Assembly Level programming language
c) Machine level programming language
7) Which best explains getSelection()?
a) Returns the VALUE of a selected OPTION.
b) Returns document.URL of the window in focus.
c) Returns the value of cursor-selected text
d) Returns the VALUE of a checked radio input.
8) What is the output of following JavaScript code?
function x()
{
var s= "Good 100%";
var pattern = /\D/g;
var output= s.match(pattern);
document.write(output);
}
a) Good %
b) 1,0,0
c) G,o,o,d,%
d) Error
9) What is the output of following JavaScript code?
var cst="SCRIPTS SOFTWARE TECHNOLOGIES";
alert(cst.charAt(cst.length-1));
a) P
b) E
c) S
d) Error
10) Choose the client-side JavaScript object:
a) Database
b) Cursor
c) Client
d) FileUpLoad
11) Are Java and JavaScript the same?
a) No
b) Yes
12) Syntax for creating a RegExp object:
(A) var txt=new RegExp(pattern,attributes);
(B) var txt=/pattern/attributes;
Which of the above mentioned syntax is correct?
a) (A) only
b) (B) only
c) Both (A) and (B)
d) None of the above
13) What is the output of following JavaScript code?
function x(z,t)
{
alert(x.length);
}
a) Error
b) 2
c) 1
d) 3
14) What is meant by "this" keyword in JavaScript?
a) It refers current object
b) It referes previous object
c) It is variable which contains value
d) None of the above
15) In JavaScript, Window.prompt() method returns true or false value?
a) False
b) True
c) None of above
16) Math. round(-20.51) = ?
b) -21
c) 19
d) None
17) What is the output of following JavaScript code?
function x()
{
var s = "Quality 100%!{[!!";
var pattern = /\w/g;
var output = s.match(pattern);
document.write(output);
}
a) %,!,{,[,!,!
b) Q,u,a,l,i,t,y,1,0,0
c) Quality 100
d) Error
18) What is the output of following JavaScript code?
var dev = new Array();
dev[0] = "Web";
dev[1] = "Development"
dev[2] = "Testing"
dev[3] = "javascript rocks";
document.write(dev[0,1,2,3]);
a) Error
b) javascript rocks
c) Web Development
d) Web, Development,Testing,javascript rocks
19) Choose the server-side JavaScript object among the following:
a) FileUpLoad
b) Function
c) File
d) Date
20) What does parseFloat(9+10) evaluates to in JavaScript?
a) 19
b) 910
c) None
21) What is the output of following JavaScript code?
function x()
{
document.write(2+5+"8");
}
a) 258
b) Error
c) 7
d) 78
22) _________ keyword is used to declare variables in javascript.
a) Var
b) Dim
c) String
23) In JavaScript, which of the following method is used to evaluate the regular expression?
a) eval(2*(3+5))
b) evaluate(2*(3+5))
c) evalu(2*(3+5))
d) None of the above
24) What is the output of following JavaScript code?
function x()
{
var s= "quality 100%";
var pattern = /\d/g;
var output= s.match(pattern);
document.write(output);
}
a) 100
b) 1,0,0
c) q,u,a,l,i,t,y,%
d) Error
25) What is the output of following JavaScript code?
var cst=((45%2)==0)?"hello":"bye";
document.write(cst);
a) hello
b) bye
c) Error in string handling
d) None of the above
26) What is the output of following JavaScript code?
function x()
{
var dev = "Scripts Software Technologies";
var pattern = new RegExp("SOFTWARE","i");
document.write(dev.match(pattern));
}
a) Error
b) SOFTWARE
c) Software
d) null
27) How do you create a new object in JavaScript?
a) var obj = {};
b) var obj = Object();
c) var obj=new {};
d) None of the above
28) What does isNaN function do in JavaScript?
a) Return true if the argument is not a number.
b) Return false if the argument is not a number.
c) Return true if the argument is a number.
d) None of the above
29) If x=103 & y=9 then x%=y , what is the value of x after executing x%=y?
a) 4
b) 3
c) 2
d) 5
30) Choose the external object among the follwing:
a) Date
b) Option
c) Layer
d) Checkbox
31) Choose the four symbol pairs that represent RegExp properties lastMatch, lastParent, leftContext, and rightContext, respectively:
a) $&, $+, $`, $'
b) $+, $&, $', $`
c) $&, $~, $`, $'
d) $+, $&, $`, $'
32) Which of the following properties hold the values of the pixels of the length of the width and height of the screen resolution?
a) screen.width and screen.height
b) Resolution.width and Resolution.height
c) screen.pixels.width and screen.pixels.height
d) ViewerScreen.width and ViewerScreen.height
33) What does ParseInt("15",10) evaluates to?
a) 15
b) 10
c) 151
d) 150
34) Which JavaScript feature uses JAR files?
a) Object signing
b) Style sheets
c) Netcaster channels
d) Image rollovers
35) How to assign a function to a variable with the JavaScript Function contructor?
a) var f=Function("x","y","return x+y");
b) var f=Function(x,y){ return x+y;}
c) var f= new Function("x", "y", "return x + y");
36) In JavaScript, Window.alert() is used to allow user to enter something
a) True
b) False
c) None of above
37) What is the output of following JavaScript code?
function x()
{
var cst = "We are fast growing Software Company located in Mumbai , India.";
var pattern = new RegExp("in","gi");
document.write(pattern.exec(cst) + " ");
document.write(pattern.exec(cst) + " ");
document.write(pattern.exec(cst) + " ");
}
a) in in In
b) in in in
c) in in null
d) in null null
38) Does JavaScript has any DATE data type?
a) Yes
b) No
39) Math.round(-20.5)=?
a) -21
b) 20
c) -20
d) 21
40) ?_name is it valid javascript identifier?
a) Yes
b) No
41) What is the output of following JavaScript code?
a) first
b) undefined
c) First
d) Error
42) Which of these comment lines are used in JavaScript?
(1) // , /* ...... **/
(2) / , /** ......./ , /*
(3) /*......*/ , //
(4) \*......*\ , //
a) Only (4)
b) Only (3)
c) Either (3) or (4)
d) Only (2)
43) What is the output of following JavaScript code?
function x()
{
var s = "Give 100%!{[!!";
var pattern = /\W/g;
var output = s.match(pattern);
document.write(output);
}
a) ,%,!,{,[,!,!
b) G,i,v,e,1,0,0
c) Give 100
d) Error
44) Which best describes void?
a) A method
b) A function
c) A statement
d) An operator
45) What is the output of following JavaScript code?
var cst="Chiasa Software Technologies";
var result =cst.lastIndexOf("a");
document.write(result);
a) 2
b) 12
c) 11
d) 13
46) What is the output of following JavaScript code?
function x()
{
var cst = "First come, first served";
var pattern = /first/g;
document.write(cst.match(pattern)[1]);
}
a) first
b) First
c) undefined
d) None of the above
47) What is the output of following JavaScript code?
If you call the function callme(), what will happen?
function sum(x)
{
function add(y)
{
return x+y;
}
return add;
}
function callme()
{
result=sum(5)(5);
alert(result);
}
a) 10
b) Error in calling Function
c) 5
d) None of the above
48) Who invented the JavaScript programming language?
a) Tennis Ritchie
b) James Gosling
c) Brendan Eich
49) Can you write HTML tags inside the JavaScript code as shown below?
document.write("This is a heading");
document.write("This is a paragraph.");
document.write("This is another paragraph.");
a) No
b) Yes
c) Impossible
50) Which feature is supported in MSIE 3.x?
a) split()
b) document.clear()
c) join()
d) charAt()
51) How to speicfy the color of the hypertext links with JavaScript?
a) document.linkColor="#00FF00";
b) document.LColor="#00FF00";
c) document.LinkC="#00FF00";
d) document.hyperTextLink="#00FF00":
52) What will be the output of following JavaScript code?
a) Position:-7
b) Position-1
c) null
d) error
53) ________ method returns the number of milliseconds in a date string.
a) setHours()
b) setMinutes()
c) parse()
54) ________ converts a string to floating point numbers.
a) eval
b) ParseInt
c) ParseFloat
d) None
55) ________ attempts to evaluate a string representing any javascript literals or variables, converting it to a number.
a) eval
b) parseFloat
c) parseInt
d) None
56) Which is not an attribute of the cookie property?
a) path
b) host
c) secure
d) domain
57) How do substring() and substr() differ?
a) One is not a method of the String object.
b) substr() takes three arguments, substring() only two.
c) Only one accepts a desired string length as an argument.
d) Besides the spelling, nothing.
58) Which is not a reserved word?
a) interface
b) short
c) program
d) throws
59) In Javascript, which of the following method is used to find out the character at a position in a string?
a) charAt()
b) CharacterAt()
c) CharPos()
d) characAt()
60) What will be the output of following JavaScript code snippter?
var cst = "PHPMB Knowledge Base Software";
var result =cst.substring(7,8);
document.write(result);
a) PHPMB Kn
b) Kn
c) ow
d) n
61) How do you delete an element from an options array?
a) Set it to false.
b) Set it to null.
c) Set it to undefined.
d) Set it to -1
62) Is JavaScript case sensitive language?
a) Yes
b) No
63) JavaScript RegExp Object has modifier 'i' to __________
a) Perform case-sensitive matching
b) Perform case-insensitive matching
c) Perform both case-sensitive&case-insensitive matching
64) What are the following looping structures are available in JavaScript?
a) for, foreach
b) foreach, whileloop
c) do-while loop, foreach
d) for, while loop
65) Which of these is not a method of the Math object?
a) atan()
b) atan2()
c) eval()
d) acos()
66) What will be the output of following JavaScript code snippter?
var s = "9123456 or 80000?";
var pattern = /\d{4}/;
var output = s.match(pattern);
document.write(output);
a) 9123
b) 91234
c) 80000
d) None of the above
67) In javascript, RegExp Object Method test() is used to search a string and returns _________
a) true or false
b) found value
c) index
d) None of the above
68) What property would you use to redirect a visitor to another page?
a) document.URL
b) window.location.href
c) document.location.href
d) link.href
69) In JavaScript, which of the statements below can be used for string declaration?
1) var dev = "javascript is awesme language ";
2) var cst=new String("javascript is awesme language");
a) Either (1) or (2)
b) Only (1)
c) Neither (1) nor (2)
d) Only (2)
70) What will be the output of following copde snippet?
var cst = "Scripts Software Technologies";
var result = cst.indexOf("Tech");
document.write(result);
a) 15
b) 16
c) 19
d) 17
71) What will be the output of following copde snippet?
function x()
{
var s = "Eat to live, but do not live to eat";
var pattern = new RegExp("eat$");
document.write(pattern.exec(s));
}
a) Eat
b) eat
c) undefined
d) Eat eat
72) What will be the output of following copde snippet?
a) in in In
b) in in in
c) in in null
d) in null null
73) -________ method is used to remove focus from the specified object.
a) blur()
b) focus()
c) None
74) What does parseFloat("FF2") evaluates to?
a) 152
b) FF2
c) NaN
d) None
75) eval((20*4)=?
a) Nan
b) 204
c) 24
d) 80
76) What will be the output of following JavaScript code?
a) null
b) Base
c) BASE
d) Error
77) JavaScript is a ________ typed language.
a) tightly
b) loosely
Answers of JavaScript Interview Quiz Questions
(1) a (2) c (3) a (4) a (5) a (6) a (7) c (8) c (9) c (10) d
(11) a (12) c (13) b (14) a (15) a (16) b (17) b (18) b (19) c (20) c
(21) d (22) a (23) a (24) b (25) b (26) d (27) a (28) a (29) a (30) d
(31) a (32) a (33) a (34) a (35) c (36) b (37) a (38) b (39) c (40) b
(41) a (42) b (43) a (44) d (45) b (46) c (47) a (48) c (49) b (50) d
(51) a (52) b (53) c (54) c (55) a (56) b (57) c (58) c (59) a (60) d
(61) b (62) a (63) b (64) d (65) c (66) a (67) a (68) b (69) a (70) b
(71) b (72) c (73) a (74) c (75) d (76) b (77) b
