Test Your JavaScript Skills : var Keyword

Introduction

Namaste, In this blog I will discuss 8 code scenarios on Javascript : var keyword .

Identify the output of the below program
```
 console.log(myval); 
 var myval=4;
```
a.4

b.null

c.undefined

d.error

e. no output

Answer:c

Reason:The var variable is hoisted
Identify the output of the below program
```
 var i=10;
 var i=12;
 console.log(i);
```
a.10

b.12

c.Error

d.undefined

e.null

Answer:b

Reason:Variable declared can be re-declared
Identify the output of the below program
```
 function fx() {
     console.log(fxval); 
     var fxval=123;
 }
 fx();
```
a.123

b.null

c. no output

d.undefined

e.error

Answer:d

Reason:The var variable is hoisted
Identify the output of the below program
```
 for (var a=10;a<15;a++) {
     a++;
 }
 console.log(a);
```
a.undefined

b.15

c.16

d.17

e.error

Answer:c

Reason:The var variable does not have block scope hence can be accessed outside

Identify the output of the below program

 function fx3() {
     try {
         var d=20;
     }catch(e) {
         console.log(e);
     }
     console.log(d); 
 }

 fx3();

a.Error

b.20

c. no output

d.undefined

e.0

Answer:b

Reason:The var variable does not have block scope

Identify the output of the below program
```
 let i=10;
 if ( i > 9){
     var c = 13;
 }
 console.log(c);
```
a.10

b.9

c.13

d.error

e.undefined

Answer:c

Reason:The var variable does not have block scope
Identify the output of the below program
```
 var i=10;
 let i=12;
 console.log("i:", i);
```
a.10

b.12

c.Error

d.Undefined

e.11

Answer: c

Reason: A variable once declared cannot be re-declared using let

Identify the output of the below program

 function fx3() {
     try {
        var d=20;
        throw new Error("Test");
     }catch(e) {
         console.log(d);
     }    
 }
 fx3();

a.20

b.Error

c.Undefined

d. No output

e.null

Answer:a

Reason:The var variable does not have block scope