javascript Array Definition and Array Length

This article provides a simple js introductory tutorial, this is an js array definition and array length example tutorial, if you are learning js array, we here tell you how to define arrays and add arrays and array length calculation examples.

Let's first look at how to define an array

var a = new array();
var b = new array(8);
var c = new array("first", "second", "third");

Or array direct quantity:

var d = ["first", "second", "third"];

Let's look at 1 and add 1 element after the array

var myarray = [];
myarray[myarray.length] = 'new element';

Length of Array

array has only one attribute, which is length length represents the number of memory occupied by the array, not just the number of elements in the array. In the array just defined, the value of b. length is 8

<script>
var a = new Array("first", "second", "third")
a[48] = "12"
document.write(a.length)
// The result displayed is 
 49
</script>

Let's take a look at an example of modifying the length of an array

var myarray = [1,2,3];
myarray.length //  The initial length is 
 3
myarray.length = 2; //  Delete the last 
 1 Elements 
 
myarray.length = 20 //  Add 
 18 Elements into an array