How to Loop Through JavaScript Array?

You can loop any Array by using different types of looping statements in JavaScript, which I have previously posted. In this post you can loop through JavaScript Array. At first let you know basic concepts of Array ie. defining array, adding values to the array and accessing array elements.

The Array object is used to store a set of values in a single variable name. You can define Array object with the new keyword.

The following line of code defines an Array object called myArray.

var myArray=new Array()

You can also define the array size by passing an integer argument as follows.

var myArray=new Array(5)

You can add the values to an array as the following.

var myArray=new Array()
myArray[0]="value1"
myArray[1]="value2"
myArray[2]="value3"

You can also give values to the arrays while defining it as below.

var myArray=new Array("value1", "value2", "value3")

While 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 line accesses the first value of the array myArray.

document.write(myArray[0])

Loop Through JavaScript Array

You can loop any Array by using any of the following looping statements in JavaScript.

Using For loop

You can loop any Array by using For Loop as below.

var myArray=new Array()
myArray[0]="value1"
myArray[1]="value2"
myArray[2]="value3"

for(i=0; i<myArray.length;i++)
{
document.write(myArray[i])
}

Example:

<html>
<head></head>
<body>
<script type="text/javascript">
var mycars=new Array()
mycars[0]="Saab"
mycars[1]="Volvo"
mycars[2]="BMW"

for(i=0; i<mycars.length;i++)
{
document.write(mycars[i]+"<br/>")
}
</script>

Preview:

Using For .... In Statement

You can loop any Array by using For .... In Statement as below.

var myArray=new Array()
myArray[0]="value1"
myArray[1]="value2"
myArray[2]="value3"

for(x in myArray)
{
document.write(myArray[x])
}

Example:

<html>
<head></head>
<body>
<script type="text/javascript">
var mycars=new Array()
mycars[0]="Saab"
mycars[1]="Volvo"
mycars[2]="BMW"

for(x in mycars)
{
document.write(mycars[x]+"<br/>")
}
</script>
</body>
</html>

Preview:

You can also loop any Array by using other looping statements like while and Do ... while loops as the same methods given above.