Javascript Reference - JavaScript Array unshift() Method

The Javascript array unshift() method adds new items to the beginning of an array, and returns its new length.

We can use the push() method to add new items to the end of an array.

The unshift() method returns undefined in Internet Explorer 8 and earlier versions.

Browser Support


`unshift()`	Yes	Yes	Yes	Yes	Yes

Syntax

array.unshift(item1,item2, ..., itemX);

Parameter Values

item1,item2, ..., itemX are the items to add to the beginning of the array.

Return Value

A Number, representing the new length of the array.

Example


var colors = new Array(); //create an array 
        //from  ww  w .  ja  v a 2s. c  o  m
var count = colors.unshift("A", "B"); //push two items 
console.log(count); //2 
count = colors.unshift("C"); //push another item on 
        
console.log(count); //3 

var item = colors.pop(); //get the first item 
console.log(item); //"B" 
console.log(colors.length); //2

The code above generates the following result.

Example 2

The following code shows how to add new items to the beginning of an array:


<!DOCTYPE html>
<html>
<body>
<button onclick="myFunction()">Test</button>
<p id="demo"></p>
<script>
var array1 = ["A", "B", "C", "D"];
document.getElementById("demo").innerHTML = array1;
<!--from   w w  w .  jav  a2 s.c o  m-->
function myFunction() {
    array1.unshift("E", "F");
    document.getElementById("demo").innerHTML = array1;
}
</script>
</body>
</html>

The code above is rendered as follows: