JavaScript

 

 

 

1.What is JavaScript?

 

It is a case-sensitive language and it is used to control the behavior of your web page.

It is also used to control the browser windows.

 

2. Mentions the some features of the JavaScript?

 

It is a client scripting language

Without page refreshing it performs some actions

It is a case-sensitive language

In the early stage it is called as live script.

 

3. What are the advantages of the JavaScript?

 

Browser compatibility

It give more powerful to web page

It is also performs validation

Create cookies

4. What are the types of js?

 

There are two types of js.

 

Internal js

External js

 

5. What is meant by internal JavaScript?

 

Implement javascript within the HTML document using <script>…</script>

 

6. What is meant by variables in JS?

 

It is like a container to store a value. In js there are two types of js

 

Local variable

Global variable

 

7. What is meant by local variable in Java script?

 

It is the variable to use variable within their function is called local variable.

 

8. What is meant by Global variable in Javascript?

 

Use variable outside of the functions is called global variables.The syntax of the global variable is

Variable-name: value;

 

9.What are the rules for variables?

 

Variable value within a quotation it will be consider as a string(var b=”10”)

 

Variable value without a quotation it will be consider as a numeric(var b=10)

 

10. Is it Javascript is a case sensitive or not?

 

Yes, Javascript is a strictly case sensitive language and it’s syntax are borrowed from Java.

 

11. What is the use of the Document.write()?

 

It is used to print statements.

 

We can able to pass statements in html by using HTML quotation

 

12. What is the use of the console.log() in JavaScript?

 

1.It is used to print statement in console window.

 

2. We can find error information using console option

 

13. What is the use of the alert()?

 

It is used to give the instruction to the user.It have only one option that is ok.

 

14.What is the use of the parselnt()?

 

It is used to convert the value into integer.

 

15.What is the use of the Prompt() in JavaScript?

 

It is used to get value from user at browser runtime. But default value will be stored in a string format.

 

16. What is the use of the confirm() in JavaScript?

 

It is same as alert.But it have two options one is OK and another one is Cancel option.

 

17. What is the meaning of the “=” in JavaScript?

 

Not only in JavaScript, In all other language It is used to assign a value.

 

18. What is the difference between “= =” and “= = =” in Javascript?

 

== it is used to check only value is equal or not.

 

=== it is used to check value and data type is equal or not.

 

19. What are the two types of Increment operators are available in JavaScript?

 

Post increment

Pre increment

 

20. What are the datatypes involved in JavaScript?

 

Number

 

String

 

Boolean

 

Function

 

Object

 

Undefined

 

 

21. What are types of errors are there in JavaScript?\

 

Logical errors

 

Runtime errors

 

Loadtime errors

 

 

 

22. What is the advantages of the blur function in JavaScript?

 

It is used to remove the focus from the specified object.This is the advantage of the blur function in JavaScript.

 

23. What are the types of message or pop boxs present in the javascript?

 

Alert()

 

Confirm()

 

Prompt()

 

parsint()

 

24. What are types of comments in JavaScript?

 

 

Single line comment

Multi line comment

 

25.Who is developed the JavaScript?

 

Javascript is developed by Brenden Eich in the year of 1995 and Netscape have the authorization.

 

26. What are the disadvantages of the Javascript?

 

It is not suitable for multithreading or multiprocessor

It is used for networking applications

It is not allowed for reading or writing files.

 

27. Mention the types of reserved words in JavaScript?

 

Abstract

Boolean

Break

Byte

Case

Catch

 

28. Is it Javascript is a object oriented language or not?

 

Yes, it is a object oriented language.

 

29. What are the two types of validations are present in javascript while performing the for validations?

 

1.Basic validation

2. Data format validation

 

 

30. What is the output of this alert(1+1+1)code?

 

The output of this code is 3

 

31.What is meant by post increment in JavaScript?

 

Actual value first printed and +1 value is incremented.

 

 

32. What is meant by post decrement?

 

Actual value first printed and -1 value is decremented.

 

 

33. What are the two types of Decrement operator available in JavaScript?

 

There are two types of decrement operator available in JavaScript.

 

Post decrement

Post increment

 

 

34. What are the two types of control structures in JavaScript?

 

Branching

Looping

 

 

35. What is the use of the Branching in JavaScript?

 

In JavaScript, It is used to checks whether conditions is true or false.

 

36. Give the syntax of the JavaScript If statement?

 

if(condition)
{
//statement;
}

 

37. What are the types of Branching in JavaScript?

 

1. If

 

2.if else

 

3. Else if

 

4. Nested if

 

5. Switch

 

38. What is the use of the Looping in the JavaScript?

 

It executes the statement first till the condition is false.Looping is three types.

 

1.For

 

2.while

 

3. Do while

 

39. Mention the features of the switch?

 

Switch is less complexity

Supports expressions

Pass conditions in different values

 

40. What is the use of “Break” statement?

 

Break keyword is used to exit an iteration or switch statement.

 

41. What is do while loop?

 

It print the statement first whether condition is true or false.Finally it will check the condition.

 

Do
{
//statement;

}
while(condition)

 

 

42. Why the “JavaScript” language called JavaScript ?

 

 

JavaScript is first called livescript. After that the syntax are borrowed from java, because of this JavaScript called JavaScript.

 

43. Which loop is used to check the multiple condition?

 

Else if is used to check the multiple condition in JavaScript.

 

Syntax:

 

if(condition)
{
//statement;
}
Else if(condition)
{
//statement;
}