The Array object lets you store multiple
values in a single variable. It stores a fixed-size sequential collection of
elements of the same type. An array is used to store a collection of data, but
it is often more useful to think of an array as a collection of variables of
the same type.
Syntax
Use the following syntax to create an Array Object.
var fruits = new Array( "apple",
"orange", "mango" );
The Array parameter is a list of strings or
integers. When you specify a single numeric parameter with the Array
constructor, you specify the initial length of the array. The maximum length
allowed for an array is 4,294,967,295.
You can create array by simply assigning values as follows:
var fruits = [ "apple",
"orange", "mango" ];
You will use ordinal
numbers to access and to set values inside an array as follows.
fruits[0] is the first element
fruits[1] is the second element
fruits[2] is the third element
Array Properties
Here is a list of the properties of the Array object along with their
description.
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Property
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Description
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constructor
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Returns a reference to the array function
that created
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the object.
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index
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The property represents the zero-based index
of the
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match in the string
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input
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This
property is only
present in arrays
created by
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regular expression matches.
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length
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Reflects the number of elements in an array.
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prototype
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The prototype property allows you to add
properties
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and methods to an object.
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In the following
sections, we will have a few examples to illustrate the usage of Array
properties.
constructor
Javascript array constructor property returns a
reference to the array function that created the instance's prototype.
Syntax
Its syntax is as follows:
array.constructor
Return Value
Returns the function that created this object's instance.
Example
Try the following example.
<html>
<head>
<title>JavaScript Array constructor
Property</title>
</head>
<body>
<script
type="text/javascript">
var arr = new Array( 10, 20, 30 );
document.write("arr.constructor is:" + arr.constructor);
</script>
</body>
</html>
Output
arr.constructor is:function Array() { [native
code] }
length
Javascript array length property returns an unsigned, 32-bit integer that specifies
the number of elements in an array.
Syntax
Its syntax is as follows:
array.length
Return Value
Returns the length of an array.
Example
Try the following example.
<html>
<head>
<title>JavaScript Array length
Property</title>
</head>
<body>
<script
type="text/javascript">
var arr = new Array( 10, 20, 30 );
document.write("arr.length is:" + arr.length);
</script>
</body>
</html>
Output
arr.length is:3
Prototype
The prototype property allows you to add
properties and methods to any object (Number, Boolean, String, Date, etc.).
Note: Prototype is a global
property which is available with almost all the objects.
Syntax
Its syntax is as follows:
object.prototype.name = value
Example
Try the following example.
<html>
<head>
<title>User-defined
objects</title>
<script
type="text/javascript">
function book(title, author){
this.title = title;
this.author = author;
}
</script>
</head>
<body>
<script
type="text/javascript">
var myBook = new
book("Perl", "Mohtashim"); book.prototype.price = null;
myBook.price = 100;
document.write("Book title is : " +
myBook.title + "<br>");
document.write("Book author is : "
+ myBook.author + "<br>");
document.write("Book
price is : " + myBook.price + "<br>"); </script>
</body>
</html>
Output
Book title is : Perl
Book author is : Mohtashim
Book price is : 100
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