Detailed explanation of array structure in JavaScript programming_Basic knowledge

The role of an array object is to store a series of values ​​using separate variable names.
Create an array and assign values ​​to it:
Example

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

What is an array?
Array objects use separate variable names to store a series of values.
If you have a set of data (for example: car name), there are separate variables as follows:

var car1="Saab";
var car2="Volvo";
var car3="BMW";

However, what if you want to identify a certain car? And not 3 cars, but 300 cars? This will not be an easy task!
The best way is to use an array.
An array can store all values ​​using a variable name, and any value can be accessed using the variable name.
Each element in the array has its own ID so that it can be easily accessed.
Create an array
There are three ways to create an array.
The following code defines an array object named myCars:
1: Conventional method:

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

2: Simple way:

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

3: Literal:

var myCars=["Saab","Volvo","BMW"];

Access array
You can access a specific element by specifying the array name and index number.
The following example provides access to the first value of the myCars array:

var name=myCars[0];

The following example modifies the first element of the array myCars:

myCars[0]="Opel";

lamp [0] is the first element of the array. [1] is the second element of the array.

In an array you can have different objects
All JavaScript variables are objects. Array elements are objects. Functions are objects.
Therefore, you can have different variable types in the array.
You can include object elements, functions, arrays in an array:

myArray[0]=Date.now;
myArray[1]=myFunction;
myArray[2]=myCars;

Array methods and properties
Use predefined properties and methods of array objects:

var x=myCars.length       // the number of elements in myCars
var y=myCars.indexOf("Volvo")  // the index position of "Volvo"

Create new method
Prototype is the JavaScript global constructor. It can construct properties and methods of new Javascript objects.
Example: Create a new method.

Array.prototype.ucase=function()
{
 for (i=0;i<this.length;i++)
 {this[i]=this[i].toUpperCase();}
}

The above example creates a new array method for converting array lowercase characters to uppercase characters.