Consider the following code snippet :
var string2Num=parseInt(123xyz);
The result for the above code snippet would be :
123
123xyz
Exception
NaN
Correct Answer :
A. 123
Explanation: The parseInt() function parses a string and returns an integer. The function returns the first integer contained in the string or 0 if the string does not begin with an integer.
Related Questions
A conditional expression is also called a _______________
Alternative to if-else
Immediate if
If-then-else statement
Switch statement
What happens in the following javaScript code snippet?
var count = 0;
while (count < 10)
{
console.log(count);
count++;
}
while (count < 10)
{
console.log(count);
count++;
}
The values of count are logged or stored in a particular location or storage
The value of count from 0 to 9 is displayed in the console
An error is displayed
An exception is thrown
Which attribute is used to specify that the script is executed when the page has finished parsing? (only for external scripts)
parse
a sync
defer
type
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 is a block statement in JavaScript?
conditional block
block that contains a single statement
both conditional block and a single statement
block that combines multiple statements into a single compound statement
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
One of the special feature of an interpreter in reference with the for loop is that ___________
Before each iteration, the interpreter evaluates the variable expression and assigns the name of the property
The iterations can be infinite when an interpreter is used
The body of the loop is executed only once
the iteration is finite when an interpreter is used
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
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
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
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);
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)
What will be the output of the following JavaScript code?
var arr=[1,2,3];
var rev=arr.reverse();
document.writeln(rev);
var rev=arr.reverse();
document.writeln(rev);
1, 2, 3
3, 2, 1
3
1
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
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 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?
var a=5 , b=1
var obj = { a : 10 }
with(obj)
{
alert(b)
}
var obj = { a : 10 }
with(obj)
{
alert(b)
}
10
Error
1
5
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 is a block statement in JavaScript?
conditional block
block that contains a single statement
both conditional block and a single statement
block that combines multiple statements into a single compound statement
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
A linkage of series of prototype objects is called as ________
prototype stack
prototype chain
prototype class
prototypes
Consider the following code snippet :
function constfuncs()
{
var funcs = [];
for(var i = 0; i < 10; i++)
funcs[i] = function() { return i; };
return funcs;
}
var funcs = constfuncs();
funcs[5]()
What does the last statement return ?
{
var funcs = [];
for(var i = 0; i < 10; i++)
funcs[i] = function() { return i; };
return funcs;
}
var funcs = constfuncs();
funcs[5]()
9
0
10
None of the mentioned
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
A conditional expression is also called a _______________
Alternative to if-else
Immediate if
If-then-else statement
Switch statement
What will be the output of the following JavaScript code?
var values=[one,two,Three];
var ans=values.shift();
document.writeln(ans);
var ans=values.shift();
document.writeln(ans);
one
two
three
error
The function stops its execution when it encounters?
continue statement
break statement
goto statement
return statement
What will be the output of the following Javascript code?
<script>
var x = 5;
var y = 2;
var z = x % y;
document.getElementById("demo").innerHTML = z;
</script>
var x = 5;
var y = 2;
var z = x % y;
document.getElementById("demo").innerHTML = z;
</script>
0
1
2
5
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
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.
for(var p in o)
console.log(o[p]);
The above code is equivalent to which code?
console.log(o[p]);
for (var i = 0;i < a.length;i++)
console.log(a[i]);
for (int i = 0;i < a.length;i++)
console.log(a[i]);
for (var i = 0;i <= a.length;i++)
console.log(a[i]);
for (var i = 1;i < a.length;i++)
console.log(a[i]);