Array object (i)

An array is a pre-defined object (also known as a Class) in JavaScript that can be used directly.

Create array object: var array = new Array ();

Creates an array object with the specified number of elements: var array = new Array (20);

Creates an array object with the specified element: var array = new Array (' Zhang San ', ' John Doe ', ' Harry ', ' Zhao Liu ');

An Array object declaration is another way of not using the new keyword, but rather using [] to include the value of the element directly, as with the effect of using the New keyword

Output the values of all the elements in the array object, remember for...in?

Attention:

Regardless of whether or not the array object is defined in advance, you can add elements to it, which is a bit of a synthesis of arrays and ArrayList in C # (Why do you say that)?
If the element is not added in indexed order, the intermediate element is populated with undefined

Array object (i)