java script Objects
Objects:
Javascript is a object oriented language which allows the
user to use predefined object (or) create user defined objects.
·
Object is a kind of data that contains
properties and methods.
·
Properties are used to hold the values that
provide the information about the object
·
Methods are the actions that are performed on
the objects
There are two ways to create objects in Javascripts
1. Direct instance
2. using functions( constructors)
1. using Direct instance:
<html>
<head>
<title>User-defined objects</title>
<script type="text/javascript">
var book = new Object(); // Create the object
book.subject = "html"; // Assign properties to the object
book.author = "Ram";
</script>
</head>
<body>
<script type="text/javascript">
document.write("Book name is : " + book.subject + "<br>");
document.write("Book author is : " + book.author + "<br>");
</script>
</body>
</html>
There are two ways to create objects in Javascripts
1. Direct instance
2. using functions( constructors)
1. using Direct instance:
<html>
<head>
<title>User-defined objects</title>
<script type="text/javascript">
var book = new Object(); // Create the object
book.subject = "html"; // Assign properties to the object
book.author = "Ram";
</script>
</head>
<body>
<script type="text/javascript">
document.write("Book name is : " + book.subject + "<br>");
document.write("Book author is : " + book.author + "<br>");
</script>
</body>
</html>
2. using constructors
<!object constructor>
<html>
<body>
<script>
function person(firstname,lastname,age,eyecolor)
{
this.firstname=firstname;
this.lastname=lastname;
this.age=age;
this.eyecolor=eyecolor;
document.write(firstname + " is " + age + " years old.");
}
myFather=new person("vijay","kumar",50,"blue");
//document.write(myFather.firstname + " is " + myFather.age + " years old.");
</script>
</body>
<!-- http://improvejavascript.blogspot.in/-->
</html>
Types of Objects:
<html>
<body>
<script>
function person(firstname,lastname,age,eyecolor)
{
this.firstname=firstname;
this.lastname=lastname;
this.age=age;
this.eyecolor=eyecolor;
document.write(firstname + " is " + age + " years old.");
}
myFather=new person("vijay","kumar",50,"blue");
//document.write(myFather.firstname + " is " + myFather.age + " years old.");
</script>
</body>
<!-- http://improvejavascript.blogspot.in/-->
</html>
Types of Objects:
- There are two types of objects are available
- 1. User Defined Objects
- 2. Predefined Objects
In JavaScript almost everything is an object.
Even primitive datatypes (except null and undefined) can be treated as objects.
- Booleans
can be objects or primitive data treated as objects
- Numbers
can be objects or primitive data treated as objects
- Strings
are also objects or primitive data treated as objects
- Dates
are always objects
- Maths
and Regular Expressions are always objects
- Arrays
are always objects
- Even
functions are always objects
1.
String object: string object can be used to perform
some operations on the string
<html>
<head>
</head>
<body>
<script type="text/javascript">
var name="java script"
document.write("name"+name+"<br/>");
document.write("length:"+name.length+"<br/>");
document.write("uppercase:"+name.toUpperCase()+"<br/>");
document.write("Lowercase:"+name.toLowerCase()+"<br/>);
document.write("ColoredText:"+name.fontcolor("red")+"<br/>");
document.write("Index:"name.indexOf("a")+"<br/>");
document.write("Last index:"+name.lastIndexOf("a")+"<br/>");
document.write("replace:"+name.replace("java","Viz")+"<br/>");
</script>
</body>
</html>
<html>
<head>
</head>
<body>
<script type="text/javascript">
var name="java script"
document.write("name"+name+"<br/>");
document.write("length:"+name.length+"<br/>");
document.write("uppercase:"+name.toUpperCase()+"<br/>");
document.write("Lowercase:"+name.toLowerCase()+"<br/>);
document.write("ColoredText:"+name.fontcolor("red")+"<br/>");
document.write("Index:"name.indexOf("a")+"<br/>");
document.write("Last index:"+name.lastIndexOf("a")+"<br/>");
document.write("replace:"+name.replace("java","Viz")+"<br/>");
</script>
</body>
</html>
1.
Date: this object is used to retrieve the date
and time.
<html>
<head>
</head>
<body>
<script type="text/javascript">
var date=new Date();
document.write("date:"+date+"<br/>");
document.write("day:"+date.getDate()+"<br/>");
document.write("Month:"+date.getMonth()+"<br/>");
document.write("Year:"+date.getYear()+"<br/>");
document.write("Hours:"+date.getHours()+"<br/>");
document.write("minutes:"+date.getMinutes()+"<br/>");
document.write("seconds:"+date.getSeconds()+"<br/>");
</script>
</body>
</html>
3. Boolean:
this object represents either true or false.
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