JavaScript Array Object

The Array object is used to store a set of values in a single variable name.

Examples

Create an array
Create an array, assign values to it, and write the values to the output.

For...In Statement
How to use a for...in statement to loop through the elements of an array.

Join two arrays - concat()
How to use the concat() method to join two arrays.

Put array elements into a string - join()
How to use the join() method to put all the elements of an array into a string.

Literal array - sort()
How to use the sort() method to sort a literal array.

Numeric array - sort()
How to use the sort() method to sort a numeric array.

Complete Array Object Reference

For a complete reference of all the properties and methods that can be used with the Array object, go to our complete Array object reference.

The reference contains a brief description and examples of use for each property and method!

Defining Arrays

The Array object is used to store a set of values in a single variable name.

We define an Array object with the new keyword. The following code line defines an Array object called myArray:

var myArray=new Array()

There are two ways of adding values to an array (you can add as many values as you need to define as many variables you require).

1:

var mycars=new Array();
mycars[0]="Saab";
mycars[1]="Volvo";
mycars[2]="BMW";

You could also pass an integer argument to control the array's size:

var mycars=new Array(3);
mycars[0]="Saab";
mycars[1]="Volvo";
mycars[2]="BMW";

2:

var mycars=new Array("Saab","Volvo","BMW");

Note: If you specify numbers or true/false values inside the array then the type of variables will be numeric or Boolean instead of string.

Accessing Arrays

You can refer to a particular element in an array by referring to the name of the array and the index number. The index number starts at 0.

The following code line:

document.write(mycars[0]);

will result in the following output:

Saab

Modify Values in Existing Arrays

To modify a value in an existing array, just add a new value to the array with a specified index number:

mycars[0]="Opel";

Now, the following code line:

document.write(mycars[0]);

will result in the following output:

Opel

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