Web Technologies

Java Script Objects

Smt M.Jeevana Sujitha

Assistant Professor

​

Department of Computer Science and Engineering

SRKR Engineering College, Bhimavaram, A.P. - 534204

OBJECTIVES

The Objectives of this lecture are

• To learn about JS Objects.

Java Script Objects

• Java script is referred as an object based programming language.

• Every object consists

of properties and

behaviors.

• Properties are values associated with an object.
• Behaviors or methods are the actions that can be performed on objects.
• Example:

var name=“srinu”; document.write(name.length); document.write(name.toUpperCase());

Java Script Objects

• Various objects in Java script are
• Date
• String
• Array
• Boolean
• Math
• RegExp

Java Script Objects

Date object: This object is used for obtaining the date and time.

• This date and time is based on computer’s local time or it can be based on GMT(Greenwich Mean Time).
• Now a days GMT is also called as UTC(Universal Coordinated Time)

Java Script Objects

Methods of Date object:

• getDate(): Returns current date based on local computer

time

• getDay(): Returns current Day. Number is from 0 to 6 i,e

from sun to sat

• getTime(): It returns the time
• getHours(): It returns the hour value ranging from 0 to 23 based on local time
• getMinutes(): Returns the minute value ranging from 0 to 59.
• getSeconds(): Returns the seconds value ranging from 0 to

59.

• getMilliseconds(): Returns milliseconds ranging from 0 to

999 based on local time.

Java Script Objects

Methods of Date object:

• getUTCDate(): Returns current date obtained from UTC
• getUTCDay(): Returns current Day based on UTC. Number

is from 0 to 6 i,e from sun to sat

• getUTCHours(): It returns the hour value ranging from 0

to 23 based on UTC timing zone

• getUTCMinutes(): Returns the minute value ranging from 0 to 59 on UTC timing zone.
• getUTCSeconds(): Returns the seconds value ranging from 0 to 59 on UTC timing zone.
• setDate(value): to set desired date using local time or UTC

timing zone.

• setHour(hr,min,sec,ms): to set desired time.

Java Script Objects

String object: String is a collection of characters.

Methods:

• concat(str): It concatenates the two strings.
• charAt(indexval): returns the character specified by index value.
• substring(beg,end): returns sub string specified by beg and end char

Java Script Objects

Methods:

letters into lower case.

• toUpperCase(): It converts

• toLowerCase(): It converts all upper case

all lower case

letters into upper case.

Example:

var s1=“sri”; var s2=“nivas”;

document.write(s1.concat(s2)); document.write(s1.charAt(1)); document.write(s1.toUpperCase());

Java Script Objects

Boolean object: This is used when we want to represent true and false values.

Example:

var tmp=new Boolean(false);

Java Script Objects

Math object: This is used for performing mathematical computations.

Methods:

• sqrt(num): Finds the square root of a num
• abs(num): Returns absolute value of a num
• ceil(num): Returns the ceil of a num Ex: ceil(10.5);
• floor(num): Returns the floor of a num Ex: floor(10.5)
• log(num): Returns log value of a num
• pow(a,b): Returns power value Ex: pow(2,5)

Java Script Objects

Methods:

• min(a,b): Returns min value of a and b Ex: min(2,4)
• max(a,b): Returns max value of a and b Ex: max(2,4)
• exp(num): Returns exp value
• sin(num):
• cos(num): Returns cos value of a num
• tan(num):

Java Script Objects

Array object: In Java script array is treated as an object.

• Array is a collection of similar type of elements which can

be referred by a common name.

Array Declaration:

• In java script the array can be created using Array

object.

Syntax:

var arrname=new Array(size);

Example:

var a=new Array(5);

Initialization:

var a=new Array(10,20,30,40,50);

var a=[10,20,30,40,50];

THANK YOU