Java Script Objects

Java Script / Java Script Objects

Object is a real world thing or entity.Object can call any method and access attributes also.

Method Accessing	Attributes Accessing
Object. Method Name(Parameters);	Object. Property name=value;

Java Script Objects

S.No	Object Name
1	Window
2	Document
3	String
4	Console
5	Number
6	Arrays
7	Date
8	Math

Window Properties

Property	Details
screenX	Returns the horizontal coordinate of the window relative to the screen
screenY	Returns the vertical coordinate of the window relative to the screen

Window Methods

Method	Example	Details
open()	window.open("https://www.w3schools.com");	Open a new window.
prompt	window.prompt("Enter no1")	Asks for data as input.
alert	window.prompt("Enter no1")	Displays the data.
close()	window.close();	close the current window.

Program	Output
<html> <head><title>Addition Program</title> </head> <script language="javascript" type="text/javascript"> function add() { var n1 = parseInt(window.prompt("Enter no1")); var n2 = parseInt(window.prompt("Enter no2")); var n3 = n1 + n2; window.alert("sum" + n3); } </script> <body> <form name="f1" > <input type="button" value="Add" name="Add" onclick="add();" /> </body> </html>	Enter no1 4 Enter no2 5 sum 9

Document Properties

Attribute	Example
bgColor	document.bgColor =”blue”;
document.body.style.backgroundColor	document.body.style.backgroundColor="blue";
document.fgColor	document.fgColor = "yellow";
document.linkColor	document.linkColor="yellow";

Document Methods

Methods	Details
Writes HTML expressions or JavaScript code to a document	Same as write(), but adds a newline character after each statement

Example: 1. Write a program to add 2 numbers.

Program	Output
<html> <body> <h1>Add Numbers</h1> <h1>5+5</h1> <button type="button" onclick="document.write(5 + 5)">Try it</button> </body> </html>	10

String
1. It is a collection of characters.
2. It can be any text inside double or single quotes. Example: var mystr = "abcd 1234";

Method	Description
length	Returns the length of a string. Example Var a = parseInt(textboxname.length); document.f1.t4.value = parseInt(t1.length);
charAt()	Returns character at the specified index (position)
concat()	Joins 2 / more strings, and returns a new joined strings
endsWith()	Checks whether a string ends with specified string/characters
includes()	Checks whether a string contains the specified string/characters
indexOf()	Returns the position of the first found occurrence of a specified value in a string
lastIndexOf()	Returns the position of the last found occurrence of a specified value in a string
match()	Searches a string for a match against a regular expression, and returns the matches
replace()	Searches a string for a specified value, or a regular expression, and returns a new string where the specified values are replaced
search()	Searches a string for a specified value, or regular expression, and returns the position of the match
split()	Splits a string into an array of substrings
startsWith()	Checks whether a string begins with specified characters
substr()	Extracts the characters from a string, beginning at a specified start position, and through the specified number of character.
substring()	Extracts the characters from a string, between two specified indices
toLowerCase()	Converts a string to lowercase letters
toString()	Returns the value of a String object
toUpperCase()	Converts a string to uppercase letters
trim()	Removes whitespace from both ends of a string

Number Object

Program	Output
<html> <body> <h2>Adition Program</h2> <p id="demo"></p> <script> var x = 123; var y = new Number(12345); document.getElementById("demo").innerHTML = x + y; </script> </body> </html>	12345

Converting Variables to Numbers

Method	Description
Number()	Returns a number, converted from its argument.
parseFloat()	Parses its argument and returns a floating point number
parseInt()	Parses its argument and returns an integer

Arrays
It collections of element all are of same data type.Number of elements are indicated by index of an array

Program	output
<html> <body> <h2>JavaScript Arrays</h2> <p id="P1"></p> <script> var abcd = ["ab", "cd", "ef"]; document.getElementById("demo").innerHTML = abcd; </script> </body> </html>	ab, cd, ef
<html> <body> <h2>JavaScript Arrays</h2> <p id="P2"></p> <script> var abcd = ["ab", "cd", "ef"]; document.getElementById("demo").innerHTML = abcd[0]; </script> </body> </html>	ab
<html> <body> <h2>JavaScript Objects</h2> <p id="P3"></p> <script> var person = { firstName: "abcd", lastName: "1234", age: 99 }; document.getElementById("demo").innerHTML = person["firstName"]; </script> </body> </html>	abcd
<html> <body> <h2>JavaScript Date Object</h2> <p id="demo1"> </p> <p id="demo2"> </p> <p id="demo3"> </p> <p id="demo4"> </p> <p id="demo5"> </p> <script> var d = new Date(); document.getElementById("demo1").innerHTML = "Year: " + d.getFullYear(); document.getElementById("demo2").innerHTML = "Year: " + d.getDate(); document.getElementById("demo3").innerHTML = "Month: " + d.getMonth(); document.getElementById("demo4").innerHTML = "Minutes:" + d.getMinutes(); document.getElementById("demo5").innerHTML = "Seconds: " + d.getSeconds(); </script> </body> </html>	JavaScript Date Object Year: 2020 Year: 17 Month: 3 Minutes:5 Seconds: 21

Math Object

Math.E // returns Euler's number
Math.PI // returns PI
Math.SQRT2 // returns square root of 2
Math.SQRT1_2 // returns square root of 1/2

Math.LN10 // returns natural logarithm of 10
Math.LOG2E // returns base 2 logarithm of E
Math.LOG10E // returns base 10 logarithm of E
Math.LN2 // returns natural logarithm of 2

Method	Returns the
abs(x)	absolute value of x
acos(x)	arccosine of x, in radians
asin(x)	arcsine of x, in radians
atan(x)	arctangent of x as a numeric value between -PI/2 and PI/2 radians
atan2(y, x)	arctangent of the quotient of its arguments
ceil(x)	value of x rounded up to its nearest integer
floor(x)	value of x rounded down to its nearest integer
exp(x)	value of Ex
log(x)	natural logarithm (base E) of x
max(x, y, z, ..., n)	number with the highest value
min(x, y, z, ..., n)	number with the lowest value
pow(x, y)	value of x to the power of y
random()	a random number between 0 and 1
round(x)	value of x rounded to its nearest integer
sqrt(x)	square root of x
sin(x)	sine of x
cos(x)	cosine of x (x is in radians)
tan(x)	tangent of an angle

Boolean
It is used to return true or false for a variable on a condition.

Program	Output
<html> <body> <script> var x = -0; document.write(Boolean(x)); </script> </body> </html>	false

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