When an empty statement is encountered, a JavaScript interpreter __________
Ignores the statement
Prompts to complete the statement
Throws an error
Shows a warning
Correct Answer :
A. Ignores the statement
Explanation: The JavaScript interpreter takes no action when it executes an empty statement. The empty statement is occasionally useful when you want to create a loop that has an empty body.
Related Questions
Consider the following code snippet
function f(o)
{
if (o === undefined) debugger;
}
What could be the task of the statement debugger?
{
if (o === undefined) debugger;
}
It does nothing but a simple breakpoint
It debugs the error in that statement and restarts the statements execution
It is used as a keyword that debugs the entire program at once
It is used to find error in the statement
What will be the equivalent code of the following JavaScript code?
o.m(x,y);
o.m(x) && o.m(y);
o[m](x,y);
o(m)[x,y];
o.m(x && y);
In the following syntax, the data type within the square brackets must be ___________
book[datatype]=assignment_value;
An integer
A String
An object
Floating point
The method or operator used to identify the array is __________
isarrayType()
==
===
typeof
What will be the output of the following JavaScript code?
function height()
{
var height = 123.56;
var type = (height>=190) ? tall : short;
return type;
}
{
var height = 123.56;
var type = (height>=190) ? tall : short;
return type;
}
123.56
190
tall
short
When does the function name become optional in JavaScript?
When the function is defined as a looping statement
When the function is defined as expressions
When the function is predefined
when the function is called
What will happen if the body of a for/in loop deletes a property that has not yet been enumerated?
The property will be stored in a cache
The loop will not run
That property will not be enumerated
The property will be enumerated
What will be the output of the following Javascript code?
function range(int length)
{
int a=5;
for(int i=0;i<length;i++)
{
console.log(a);
}
}
range(3);
{
int a=5;
for(int i=0;i<length;i++)
{
console.log(a);
}
}
range(3);
5
555
3
error
Do functions in JavaScript necessarily return a value?
It is mandatory
Not necessary
Few functions return values by default
some functions do not return any value
If you have a function f and an object o, you can define a method named m of o with
o.m=m.f;
o.m=f;
o=f.m;
o=f;
What will be the output of the following Javascript code?
int a=0;
for(a;a<5;a++);
console.log(a);
for(a;a<5;a++);
console.log(a);
0
error
4
5
A function with no return value is called ___________
Procedures
Method
Static function
Dynamic function
What is the difference between the two lines given below ?
!!(obj1 && obj2);
(obj1 && obj2);
(obj1 && obj2);
Both the lines result in a boolean value True
Both the lines result in a boolean value False
Both the lines checks just for the existence of the object alone
The first line results in a real boolean value whereas the second line merely checks for the existence of the objects
What will be the output of the following JavaScript code?
var a1 = [,,,];
var a2 = new Array(3);
0 in a1
0 in a2
var a2 = new Array(3);
0 in a1
0 in a2
true false
false true
true true
false true
What will be the output of the following JavaScript code?
function output(object)
{
var place=object ? object.place : Italy;
return clean:+ place;
}
console.log(output({place:India}));
{
var place=object ? object.place : Italy;
return clean:+ place;
}
console.log(output({place:India}));
clean:India
clean:Italy
error
undefined
Which is an equivalent code to invoke a function m of class o that expects two arguments x and y?
o(x,y);
o.m(x) && o.m(y);
m(x,y);
o.m(x,y);
What will be the output of the following JavaScript code?
function code(id,name)
{
this.id = id;
this.name = name;
}
function pcode(id,name)
{
code.call(this,id,name);
}
document.writeln(new pcode(101,vivek).id);
{
this.id = id;
this.name = name;
}
function pcode(id,name)
{
code.call(this,id,name);
}
document.writeln(new pcode(101,vivek).id);
vivek
101
Runtime error
Compilation error
What will be the output of the following JavaScript code?
var grade='A';
var result;
switch(grade)
{
case 'A':
result+=10;
case 'B':
result+= 9;
case 'C':
result+= 8;
default:
result+= 0;
}
document.write(result);
var result;
switch(grade)
{
case 'A':
result+=10;
case 'B':
result+= 9;
case 'C':
result+= 8;
default:
result+= 0;
}
document.write(result);
10
27
8
0
What are the three important manipulations done in a for loop on a loop variable?
Updation, Incrementation, Initialization
Initialization,Testing, Updation
Testing, Updation, Testing
Initialization,Testing, Incrementation
The escape sequence stands for _________
Floating numbers
Representation of functions that returns a value
is not present in JavaScript
Form feed
A conditional expression is also called a _______________
Alternative to if-else
Immediate if
If-then-else statement
Switch statement
What will be the firstname and surname of the following JavaScript code?
var book = {
main title: JavaScript,
'sub-title': The Definitive Guide,
for: all audiences,
author: {
firstname: David,
surname: Flanagan
}
};
main title: JavaScript,
'sub-title': The Definitive Guide,
for: all audiences,
author: {
firstname: David,
surname: Flanagan
}
};
properties
property values
property names
objects
The primary purpose of the array map() function is that it __________
maps the elements of another array into itself
passes each element of the array and returns the necessary mapped elements
passes each element of the array on which it is invoked to the function you specify, and returns an array containing the values returned by that function
pass the elements of the array into another array
Assume that we have to convert false that is a non-string to string. The command that we use is (without invoking the new operator).
false.toString()
String(false)
String newvariable=false
Both false.toString() and String(false)
In the following switch syntax, the expression is compared with the case labels using which of the following operator(s)?
switch(expression)
{
statements
}
{
statements
}
==
equals
equal
===
What will be the step of the interpreter in a jump statement when an exception is thrown?
The interpreter stops its work
The interpreter throws another exception
The interpreter jumps to the nearest enclosing exception handler
The interpreter throws an error
What will be the output of the following JavaScript code?
int a=1;
if(a!=null)
return 1;
else
return 0;
if(a!=null)
return 1;
else
return 0;
1
0
runtime error
compiler error
The var and function are __________
Keywords
Declaration statements
Data types
Prototypes
Which is a more efficient JavaScript code snippet?
Code 1 :
for(var num=10;num>=1;num--)
{
document.writeln(num);
}
Code 2 :
var num=10;
while(num>=1)
{
document.writeln(num);
num++;
}
{
document.writeln(num);
}
while(num>=1)
{
document.writeln(num);
num++;
}
Code 1
Code 2
Both Code 1 and Code 2
Cannot Compare
What will be the output of the following Javascript code?
var add=new Function(num1,num2,return num1+num2);
document.writeln(add(2,5));
document.writeln(add(2,5));
2
5
Error
7