What is the observation made in the following JavaScript code?
if (!a[i]) continue;
Skips the defined elements
Skips the existent elements
Skips the null elements
Skips the defined & existent elements
Correct Answer :
C. Skips the null elements
Explanation: The if loop in the above code checks whether the value of a[i] exists or not. For undefined, non existent and null values the if loop returns true.
Related Questions
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>10)
{
document.write(10);
}
else
{
document.write(a);
}
if(a>10)
{
document.write(10);
}
else
{
document.write(a);
}
10
0
1
Undefined
The var and function are __________
Keywords
Declaration statements
Data types
Prototypes
What will be the output of the following JavaScript code?
function compare()
{
int a=1;
char b=1;
if(a.tostring()===b)
return true;
else
return false;
}
{
int a=1;
char b=1;
if(a.tostring()===b)
return true;
else
return false;
}
true
false
runtime error
logical error
What will be the output of the following JavaScript code?
Int a=1;
if(a>10)
{
document.write(10);
}
else
{
document.write(a);
}
if(a>10)
{
document.write(10);
}
else
{
document.write(a);
}
10
0
1
Undefined
The basic purpose of the toLocaleString() is to _________
return a localised object representation
return a parsed string
return a local time in the string format
return a localized string representation of the object
What will be the output of the following JavaScript code?
string a = hi;
string b =there;
alert(a+b);
string b =there;
alert(a+b);
hi
there
hithere
undefined
What will be the equivalent output of the following JavaScript code snippet?
x = ~-y;
w = x = y = z;
q = a?b:c?d:e?f:g;
w = x = y = z;
q = a?b:c?d:e?f:g;
x = ~(-y); w = (x = (y = z));
q = a?b:(c?d:(e?f:g));
x = a?b:(c?d:(e?f:g));
q = ~(-y); w = (x = (y = z));
x = (x = (y = z));w = ~(-y);
q = a?b:(c?d:(e?f:g));
x = ~(-y); w = (x = (y = z));
q = (c?d:(e?f:g));
What will be the output of the following JavaScript code?
var val1=[1,2,3];
var val2=[6,7,8];
var result=val1.concat(val2);
document.writeln(result);
var val2=[6,7,8];
var result=val1.concat(val2);
document.writeln(result);
1, 2, 3
Error
1, 2, 3, 6, 7, 8
123
The web development environment (JavaScript) offers which standard construct for data validation of the input entered by the user.
Controlled loop constructs
Case checking constructs
Validation constructs
All of the mentioned
Consider the following code snippet.
while (a != 0)
{
if (a == 1)
continue;
else
a++;
}
What will be the role of the continue keyword in the above code snippet?
{
if (a == 1)
continue;
else
a++;
}
The continue keyword restarts the loop
The continue keyword skips the next iteration
The continue keyword skips the rest of the statements in that iteration
The continue keyword breaks out of the loop
What will be the output of the following JavaScript code?
var values=[1,2,3,4]
var ans=values.slice(1);
document.writeln(ans);
var ans=values.slice(1);
document.writeln(ans);
1, 2, 3, 4
2, 3, 4
1, 3, 4
error
The purpose of extensible attribute is to __________
make all of the own properties of that object non configurable
to configure and bring a writable property
lock down objects into a known state and prevent outside tampering
to include new properties into the object
The method or operator used to identify the array is __________
isarrayType()
==
===
typeof
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 be the output of the following Javascript code?
var a=3.7;
var b=2;
a=ciel(a)
document.writeIn(a*b);
var b=2;
a=ciel(a)
document.writeIn(a*b);
6
7.4
7.5
8
JavaScript Code can be called by using ___________
RMI
Triggering Event
Preprocessor
Function/Method
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?
7.25
-7.25
7
-7
What will be the output of the following JavaScript code?
var grade='E';
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
0
18
17
An expression that can legally appear on the left side of an assignment expression. is a well known explanation for variables, properties of objects, and elements of arrays. They are called ___________
Properties
Prototypes
Lvalue
Definition
What will be the output of the following JavaScript code?
int sum=0;
var arr = [10,15,20,30];
arr.forEach(function myFunction(element)
{
sum= sum+element;
});
document.writeln(sum);
var arr = [10,15,20,30];
arr.forEach(function myFunction(element)
{
sum= sum+element;
});
document.writeln(sum);
70
75
10
error
What will be the output of the following JavaScript code?
125
25
5
Error
A function with no return value is called ___________
Procedures
Method
Static function
Dynamic function
What will be the output of the following JavaScript code?
const object1 = {
property1: 20
};
console.log(Object.is(object1));
property1: 20
};
console.log(Object.is(object1));
20
true
false
error
The escape sequence stands for _________
Floating numbers
Representation of functions that returns a value
is not present in JavaScript
Form feed
What will be the output of the following JavaScript code?
var grade='B';
var result;
switch(grade)
{
case 'A':
{
result+=10;
break;
}
case 'B':
{
result+= 9;
break;
}
case 'C':
{
result+= 8;
break;
}
default:
result+= 0;
}
document.write(result);
var result;
switch(grade)
{
case 'A':
{
result+=10;
break;
}
case 'B':
{
result+= 9;
break;
}
case 'C':
{
result+= 8;
break;
}
default:
result+= 0;
}
document.write(result);
10
9
8
0
What will be the output of the following JavaScript code?
const obj1 = { property1: '10'};
const obj2 = Object.freeze(obj1);
obj2.property1 = '20';
console.log(obj2.property1);
const obj2 = Object.freeze(obj1);
obj2.property1 = '20';
console.log(obj2.property1);
10
20
Runtime error
Compilation error
What will the following code snippet work? If not, what will be the error?
function tail(o)
{
for (; o.next; o = o.next) ;
return o;
}
{
for (; o.next; o = o.next) ;
return o;
}
No, this will throw an exception as only numerics can be used in a for loop
No, this will not iterate
Yes, this will work
No, this will result in a runtime error with the message Cannot use Linked List
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